Backdoor.Sogu

Sogu is a backdoor Trojan that may be used as a preliminary step between the initial infection of a PC and the installation of high-level threats, such as the PoisonIvy RAT. Because of their strong association with Axiom, a Chinese hacker organization, Sogu Trojans are significant security risks for government and business networks, with spearhead attacks disguised as 'safe' e-mail attachments. Removing Sogu, like any Trojan capable of creating backdoor vulnerabilities, should include the use of anti-malware tools that can delete all of its components and potentially threatening settings changes.

Fighting for Your Rights against a Sogu Trojan

Sogu is a Trojan sometimes deployed in targeted e-mail attacks against political rights activists, particularly in Asia. Also known by PlugX, Kaba, DestroyRAT, Thoper or Korplug, Sogu may provide general backdoor functions that could be used to install other threatening software, change your PC's security settings or run system commands. In these respects, Sogu is similar to other backdoor Trojans also associated with Axiom, such as Fexel or Naid. Distribution methods confirmed for Sogu also use one of Axiom's favored tactics: a threatening e-mail attachment.

File attachments seeded with Trojan droppers for installing Sogu Trojans may disguise with file formats common to Microsoft Office, such as XLS or DOC. Opening the offending document may trigger the installation of Sogu, allowing third parties to gain full access to the affected PC. A legitimate document also may be opened during Sogu's installation, seemingly to distract the victim from the attack. As a result, third parties easily could use Sogu to bypass the network firewall or install other threats with even more in-depth attack features than Sogu.

Some versions of Sogu Trojans also included spyware-associated functions, such as keylogging or taking screen captures. These attacks enabled the theft of information, automatically transferred over to a C&C server.

Taking a Lesson in E-mail Safety to Heart

Sogu's attacks don't corroborate to any hard-defined symptoms. Even the presence of files on your hard drive may be uncertain; malware experts have observed 'no-file' memory-injecting attacks from Sogu similar to those of Naid, another Trojan tied to Axiom. The clearest evidence of a Sogu attack is the initial opening of an exploit-hosting file attachment, which updated anti-malware products should be able to confirm as threatening.

Sogu is specific to Windows computers, and, like many threats from Axiom, may be used in attacks against specific non-profits, governments and corporations. Routine anti-malware scans of all systems suspected for being at risk of Sogu campaigns should provide all the protection needed, in the event of a failure of standardized e-mail security. However, outdated security tools are likely to be poorly-equipped to deal with Sogu. The Axiom group has a long history for creating new, specialized variants of old threats, including Sogu variants that could avoid old detection heuristics.

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