A newly discovered tool used to disable endpoint detection and response (EDR) software has been attributed to the RansomHub ransomware group, a cybercrime syndicate with suspected ties to the rebranded Knight ransomware. The tool, named “EDRKillShifter” by cybersecurity firm Sophos, was uncovered during a failed ransomware attack in May 2024. It joins the ranks of similar tools like AuKill and Terminator, designed specifically to neutralize EDR defenses on compromised systems. EDRKillShifter operates as a “bring your own vulnerable driver” (BYOVD) utility, using legitimate but exploitable drivers to escalate privileges and disable security software, making it a significant threat in the hands of sophisticated attackers.
The EDRKillShifter tool works by executing a command-line script accompanied by a password string, which decrypts and runs an embedded resource named BIN. This resource unpacks and executes a final Go-based payload that leverages different vulnerable drivers to gain elevated privileges. Notably, the binary’s language settings indicate it was compiled on a system with Russian localization, further suggesting its origin. By embedding the vulnerable driver within its .data section, the tool can effectively bypass EDR software, leaving systems exposed to further malicious activities.
RansomHub, believed to be a rebranded version of the Knight ransomware, surfaced in February 2024. The group is known for exploiting known security flaws to gain initial access and deploying legitimate remote desktop tools like Atera and Splashtop to maintain persistence. In a recent development, Microsoft revealed that Scattered Spider, a notorious e-crime syndicate, has incorporated both RansomHub and Qilin ransomware strains into its toolkit, indicating the growing threat posed by these groups.
In addition to EDRKillShifter, threat actors have been observed deploying a new malware called SbaProxy, which modifies legitimate antivirus binaries from companies like BitDefender and Malwarebytes. By signing these files with counterfeit certificates, SbaProxy establishes proxy connections through a command-and-control (C2) server, routing traffic between the infected machine and the target.
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