‘Clandestine Fox’ hackers win over energy employee in strategy change

A hard-to-tracking hacking group, known to use zero-day attacks, changed tack to use social media in an attempt to compromise an employee of an energy company, according to new research from FireEye.

FireEye declined to say who conducted the attack other than it was the same group that ran a campaign it dubbed “Operation Clandestine Fox,” which it described in April and early May. It also did not identify where the employee works.

FireEye’s subsidiary, Mandiant, is notable for outing in February 2013 a Shanghai-based Chinese Army signals intelligence branch, Unit 61398, which it said in a report was responsible for running wide-ranging hacking campaigns against U.S. industry. It called the group APT1, short for Advanced Persistent Threat.

Last month, U.S. prosecutors filed an unprecedented criminal indictment against five members of the unit, alleging they stole intellectual property and, in some cases, gave it to Chinese companies. China fumed and denied the accusations.

FireEye’s latest research describes how an attacker, which it nicknamed “Emily,” courted the energy employee’s colleagues on a social network. She peppered them with probing questions, such as the name of the IT manager for the company and what type of software they ran, according to Mike Scott, a senior threat analyst at FireEye.

Eventually, Emily contacted the employee via the social network and the two corresponded for three weeks. She eventually sent him her resume in a “.rar” archive to his personal email address.

The archive file had a PDF of her resume but also a malicious version of TTCalc, which is an open source calculator. When executed, the malicious TTCalc installed a benign version of itself but also slipped a backdoor onto the computer.

The attack is different from other campaigns by the group in that this required tricking the victim. In the past, the group has relied on a number of browser-based zero-day exploits, or attacks that take advantage of a software vulnerability, which often require little user interaction aside from navigating to a malicious web page.

FireEye linked this attack to previous ones because the attackers utilized a domain name it had used in the past as part of its command-and-control structure. That was perhaps a glaring error on the part of the attackers, as FireEye had noted in a previous blog post that the group typically does “not reuse command and control infrastructure.”

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