Researchers discovered a new FuxSocy ransomware strain that employs several of the same techniques as the notorious Cerber malware family.
As reported by Bleeping Computer, reverse engineer Vitali Kremez analyzed a sample of FuxSocy — a name that draws inspiration from the FSociety hacking group from the “Mr. Robot” TV series — and observed the ransomware using a modified list taken directly from Cerber, specifying which folders it should avoid encrypting based on their strings. Kremez also observed FuxSocy prioritizing certain folders for encryption and scrambling file names and extensions, behaviors that resemble those of Cerber. When it finished with its encryption routine, according to the report, the threat changed the desktop background to appear nearly identical to Cerber’s.
Even so, Kremez found important differences between the two cryptomalware families. For example, unlike Cerber, FuxSocy looks for processes, files and named pipes to prevent users from executing the ransomware on a virtual machine. FuxSocy also encrypts only a portion of an affected file and asks the victim to contact the threat actors using the ToxChat messaging app, while Cerber encrypts the whole file and directs victims to visit a Tor payment site.
A Brief History of Cerber Ransomware
Cerber was one of the most significant ransomware families of its time. In May 2017, Trend Micro detected the sixth version of the family using a ransomware-as-a-service (RaaS) model, anti-evasion techniques and other tactics to maximize its profits.
A few months later, Malwarebytes observed the Magnitude exploit kit using a configuration file that appended junk data onto the existing Cerber binary so that it could “inflate” its size past the scanning limits of many security solutions.
Although Cerber went quiet in mid-September, a month later, Bleeping Computer spotted Magniber ransomware and interpreted it to be Cerber’s successor.
How Can Companies Defend Against FuxSocy Ransomware?
Security professionals can help defend against FuxSocy ransomware by developing and regularly testing an incident response plan that includes processes to quickly address a crypto-malware infection. Organizations should also invest in patch management to keep their endpoints’ hardware and software up to date.