KrebsOnSecurity recently featured the story of a Brazilian man who was peppered with phishing attacks trying to steal his Apple iCloud username and password after his wife's phone was stolen in a brazen daylight mugging. Today, we'll take an insider's look at an Apple iCloud phishing gang that appears to work quite closely with organized crime rings — within the United States and beyond — to remotely unlock and erase stolen Apple devices.

Victims of iPhone theft can use the Find My iPhone feature to remotely locate, lock or erase their iPhone — just by visiting Apple's site and entering their iCloud username and password. Likewise, an iPhone thief can use those iCloud credentials to remotely unlock the victim's stolen iPhone, wipe the device, and resell it. As a result, iPhone thieves often subcontract the theft of those credentials to third-party iCloud phishing services. This story is about one of those services.

Recently, I heard from a security professional whose close friend received a targeted attempt to phish his Apple iCloud credentials. The phishing attack came several months after the friend's child lost his phone at a public park in Virginia. The phish arrived via text message and claimed to have been sent from Apple. It said the device tied to his son's phone number had been found, and that its precise location could be seen for the next 24 hours by clicking a link embedded in the text message.

That security professional source — referred to as "John" for simplicity's sake — declined to be named or credited in this story because some of the actions he took to gain the knowledge presented here may run afoul of U.S. computer fraud and abuse laws.

John said his friend clicked on the link in the text message he received about his son's missing phone and was presented with a fake iCloud login page: appleid-applemx[dot]us. A lookup on that domain indicates it is hosted on a server in Russia that is or was shared by at least 140 other domains — mostly other apparent iCloud phishing sites — such as accounticloud[dot]site; apple-appleid[dot]store; apple-devicefound[dot]org; and so on (a full list of the domains at that server is available here).

While the phishing server may be hosted in Russia, its core users appear to be in a completely different part of the world. Examining the server more closely, John noticed that it was (mis)configured in a way that leaked data about various Internet addresses that were seen recently accessing the server, as well as the names of specific directories on the server that were being accessed.

After monitoring that logging information for some time, my source discovered there were five Internet addresses that communicated with the server multiple times a day, and that those address corresponded to devices located in Argentina, Colombia, Ecuador and Mexico.

He also found a file openly accessible on the Russian server which indicated that an application running on the server was constantly sending requests to imei24.com and imeidata.net — services that allow anyone to look up information about a mobile device by entering its unique International Mobile Equipment Identity (IMEI) number. These services return a variety of information, including the make and model of the phone, whether Find My iPhone is enabled for the device, and whether the device has been locked or reported stolen.

John said that as he was conducting additional reconnaissance of the Russian server, he tried to access "index.php" — which commonly takes one to a site's home page — when his browser was redirected to "login.php" instead. The resulting page, pictured below, is a login page for an application called "iServer." The login page displays a custom version of Apple's trademarked logo as part of a pirate's skull and crossbones motif, set against a background of bleeding orange flames.

John told me that in addition to serving up that login page, the server also returned the HTML contents of the "index.php" he originally requested from the server. When he saved the contents of index.php to his computer and viewed it as a text file, he noticed it inexplicably included a list of some 137 user names, email addresses and expiration dates for various users who'd apparently paid a monthly fee to access the iCloud phishing service.

"These appear to be 'resellers' or people that have access to the crimeware server," my source said of the user information listed in the server's "index.php" file.

John told KrebsOnSecurity that with very little effort he was able to guess the password of at least two other users listed in that file. After John logged into the iCloud phishing service with those credentials, the service informed him that the account he was using was expired. John was then prompted to pay for at least one more month subscription access to the server to continue.

Playing along, John said he clicked the "OK" button indicating he