text
stringlengths 4
429
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#### is a number)
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Potential variation
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SYSTEM\CurrentControlSet\Services\
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RaS???\Parameters\
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Value: ServiceDLL
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Data: %temp%\c_1758.nls
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PAYLOAD
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The payload uses
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two-stage installation. GLANCE UNDER THE HOOD
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buffer after phase one XOR:
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During stage one, the
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mJ2bhcPExs7excLThcjExqurnauYq
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dropper will install the
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buffer after base64 decoding:
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payload as a service
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running under the
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name Ups??? (where
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??? are three random characters). Once executing, the
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payload will immediately delete the first service and enter
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stage-two. During stage-two, the payload will register a new,
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second service under the name RaS??? (where ??? are three
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random characters). This new service will point to the same
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backdoor DLL, no new files are involved. Note: the three
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character prefixes Ups and RaS can easily be modified by
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the attacker.
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Once the new service is registered, the payload will access
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an embedded resource that is encrypted. The decryption goes
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through several phases. The encrypted data block contains
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the DNS name for the command and control server (homeunix.
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com, etc). This data block is configurable before the malware
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is deployed. The data block length is hard-coded (0x150 or
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336 bytes). During phase one, this data block is fed through
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a simple XOR (0x99), resulting in an ASCII-string. Next, the
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resulting ASCII-string is fed into a base64 decoding function,
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producing a binary string. Finally, the resulting base64
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decoded binary string is fed through another XOR (0xAB),
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resulting in clear-text. The three primary encryption loops are
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colored and marked in Figure 1. The resulting clear-text buffer
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contains several fields in both ASCII and UNICODE, including
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the C&C server address.
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Figure 1. Base64 and XOR Encryption Scheme
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HB GARY THREAT REPORT: OPERATION AURORA
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ACTIONABLE INTELLIGENCE
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PATTERN
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C&C Server DNS
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* .homeunix.com
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(where * is any subdomain)
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* .homelinux.com
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* .ourhobby.com
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COMMAND AND CONTROL
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The payload communicates with its command and control
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server over port 443. The source port is randomly selected.
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While outbound traffic appears to be HTTPS, the actual traffic
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uses a weak custom encryption scheme. The command and
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control packets have a very specific format.iv
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* .3322.org
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* .2288.org
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command
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parms
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0x00000001
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payload len CRC KEY payload
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* .8866.org
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* .ath.cx
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* .33iqst.com
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* .dyndns.org
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* .linode.com
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* .ftpaccess.cc
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* .filoups.info
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* .blogsite.org
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The payload will create additional registry keys.
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ACTIONABLE INTELLIGENCE
|
PATTERN
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Additional Key
|
HKLM\Software\Sun\1.1.2\IsoTp
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Additional Key
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HKLM\Software\Sun\1.1.2\AppleTlk
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The payload section is encrypted with a key selected by
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using GetTickCount. This means each infected node has its own
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key. The key is embedded in the header of the packet, and is
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easily recovered.
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DIAGNOSE
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HOW THE MALWARE WORKS
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The primary control logic can be found in the module
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registered under the service key (rasmon.dll, etc.). This
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module has been written in c and includes several specific
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methods and encodings that provide forensic track-ability.
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Other potential dropped files, as reported by McAfee:
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ACTIONABLE INTELLIGENCE
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PATTERN
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Additional File
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securmon.dll
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Additional File
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AppMgmt.dll
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Additional File
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A0029670.dll (A00#####.dll)
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Additional File
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msconfig32.sys
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Additional File
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VedioDriver.dll
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Additional File
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