Description

Security researchers recently identified two previously undisclosed endpoints in older versions of Cortex XDR agents, which had been compromised through the use of an AV/EDR bypass tool, likely sourced from underground cybercrime forums. The tool, disabler.exe, based on the EDR Sand Blast source code, exploits a vulnerable driver (wnbios.sys or WN_64.sys) to remove EDR hooks, allowing privileged access and bypassing security measures. Analysis of the compromised system’s Z:\freelance directory revealed usernames linked to potential cybercrime affiliates. The threat actor, identified as Marti71, had been actively seeking AV/EDR bypass tools on underground forums like XSS and Exploit, where they likely obtained the tool. Positive feedback from other users confirmed the tool’s effectiveness. The system also contained an archive, ContiTraining.rar, which pointed to leaked Conti materials, including penetration testing tools, exploit manuals, and sensitive financial data. Other files included hacking tools such as Mimikatz, AV/EDR bypass utilities, and kernel driver exploits, indicating advanced capabilities. Furthermore, the attack utilized tools like Atera, Cobalt Strike, and PsExec, mirroring tactics of known groups like Conti and Dark Scorpius. While no ransomware was deployed, the attack displayed characteristics of an APT. A suspect, identified as Andry, a Kazakhstani national, was linked to the attack after an operational security failure exposed his profiles on LinkedIn and VKontakte. This incident highlights the growing sophistication of AV/EDR bypass tools, which continue to circulate on underground forums, enabling attackers to evade security defences and conduct sophisticated, targeted attacks.