A new piece of malware making the rounds intercepts Skype communications and takes custom backdoor software a step forward, according the researchers with Palo Alto Networks, who discovered it. Dubbed T9000, the malware contains a host of cybercriminal bells and whistles.
"Most custom backdoors used by advanced attackers have limited functionality. They evade detection by keeping their code simple and flying under the radar. But during a recent investigation we found a backdoor that takes a very different approach," say researchers Josh Grunzweig and Jen Miller-Osborn. "In addition to the basic functionality all backdoors provide, T9000 allows the attacker to capture encrypted data, take screenshots of specific applications, and specifically target Skype users."
The backdoor may be remarkable in all of the added functionality and evasion techniques packed into it, but each flourish is pretty typical of today's attacker modus operandi. For example:
Reveal 1: Evolved From Another Piece Of Malware
Like many pieces of malware today, T9000 is evolved from a previous incarnation, T5000 (AKA Plat1, which was first discovered by Cylance back in 2013. Security researchers have found time and again that the majority of malware is based on recycled code.
Reveal 2: Used In Targeted Attacks To Collect Intel On Targets
Grunzweig and Miller-Osborn report that T9000 has been used in a number of targeted attacks against U.S. organizations. The main purpose of this malware is to gather some serious dirt on the victims.
"In fact, the author chose to store critical files dropped by the Trojan in a directory named 'Intel,'" the wrote. "T9000 is pre-configured to automatically capture data about the infected system and steal files of specific types stored on removable media."
This includes taking screencaps from Skype video calls, recording calls in their entirety, tracking chat messages and collect tons of other files across the entire system.
Reveal 3: Distributed By Spearphishing With A Malicious RTF File
T9000 appears to be delivered via spearphishing using a malicious RTF to set the chain of infection in motion. The document is crafted using exploits against a nearly four-year-old ActiveX vulnerability in Microsoft Office and a year-old Microsoft Office memory corruption vulnerability. According to Sean Wilson with PhishMe, the firm has recently seen an increase of malware samples like T9000 taking advantage of RTF temp files as a way to encapsulate and drop malware.
Reveal 4: Anti-malware Evasion
"The malware goes to great lengths to identify a total of 24 potential security products that may be running on a system and customizes its installation mechanism to specifically evade those that are installed," Grunzweig and Jen Miller-Osborn wrote.
Attackers are increasingly jumping through hoops to add evasive tactics like these to their malware. In a presentation for RSA Conference 2015, Dr. Christopher Kruegel with Lastline reported that evasive techniques used by malware doubled last year.
Reveal 5: Multi-stage Installation
T9000 engages in a mult-stage installation process that starts with that check for the aforementioned security products and customizes the files it drops according to that and a number of system-state variables.
Multi-stage attacks have become the preferred method of getting malware fully installed on systems, giving attackers maximum flexibility in evasion techniques.
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