Sophos uncovers unusual malware targeting users of pirated software

New research, published by Sophos, has found an unusual cyberattack campaign that targets users of pirated software with malware designed to block access to websites hosting pirated software.

The malware is disguised as cracked versions of popular online games, such as Minecraft and Among Us, as well as productivity tools like Microsoft Office, security software, and others. The malware is then distributed via BitTorrent from an account hosted on ThePirateBay, with links also hosted on Discord. Once installed, the malware blocks the victims access to a long list of websites, including many that distribute pirated software.

Some curious aspects of the attack include:

• The attackers are using an old approach of modifying the HOSTS file settings on an infected device to localhost a long list of websites, blocking the users access to them. This approach is fairly easy to reverse, and Sophos researchers are unsure why the attackers used it.
• Some, of the many hundreds of sites that are being localhosted by the malware, are unrelated to pirated software and some were shut down or became inactive in or around 2012/2013.
• The malicious files are compiled for 64-bit Windows 10 and then signed with false digital certificates that wouldn't pass more than a rudimentary check.
• Once downloaded and installed by a user, the malware searches for files named 7686789678967896789678 and 412412512512512. If it finds them, it stops any further launch of the attack. Sophos believes this could be designed to prevent the malware operators from infecting their own computers while they work on the malicious code.
• The malware also triggers a fake error message to appear when it runs, which asks people to re-install the software. Sophos says this could be to dispel suspicion among users who question why the download they received didn't contain the installers they were expecting.

"Sometimes it is easy to see clearly what an adversary's end game is and why they have chosen a particular approach to achieve it," says Sophos principal threat researcher, Andrew Brandt.

"This is not one of those times. On the face of it, the adversary's targets and tools suggest this could be some kind of crudely-compiled anti-piracy vigilante operation.

"However, the attackers vast potential target audience from gamers to business professionals, combined with the curious mix of dated and new tools, techniques, and procedures, and the bizarre list of websites blocked by the malware, all make the ultimate purpose of this operation a bit murky.

He says there may not even be an overall purpose to this attack. However, that doesn't reduce the level of risk or the potential disruption for victims.