Description

FIN8, a financially motivated cybercrime group also known as Syssphinx, has been detected employing an enhanced version of the Sardonic malware to distribute the BlackCat ransomware. Operating since January 2016, FIN8 primarily targets industries such as retail, restaurants, hotels, healthcare, and entertainment. Researchers from BitDefender have highlighted the extensive toolkit employed by this threat actor, which includes various POS malware variants like BadHatch, PoSlurp/PunchTrack, and PowerSniff/PunchBuggy/ShellTea. Additionally, FIN8 has been known to exploit Windows zero-day vulnerabilities and conduct spear-phishing campaigns. In 2021, BitDefender observed a shift from BadHatch to the C++-based backdoor Sardonic, enabling information collection, command execution, and the installation of malicious DLL modules. Symantec's Threat Hunter Team discovered an upgraded version of the Sardonic backdoor during attacks in December 2022. While it possessed similar capabilities to the BitDefender variant, most of the backdoor code had been updated, resulting in a revised appearance. Interestingly, the latest variation of the backdoor no longer utilizes the C++ standard library, and many object-oriented functionalities have been replaced with a simpler C implementation. Researchers also noted that some of the changes made to the backdoor code appeared unnatural, likely aimed at avoiding similarities with previously disclosed information. However, other techniques employed by Syssphinx remain unchanged from their previous operations. It is worth mentioning that FIN8 has expanded its strategy from Point-of-Sale (POS) attacks to include ransomware attacks, increasing their potential profits. Symantec researchers emphasized that Syssphinx (FIN8) continually strives to develop and enhance its capabilities and malware distribution infrastructure, regularly upgrading tools and techniques to evade detection. The development and use of the new Sardonic malware variant in December 2022 are part of this ongoing effort.