Teams TURN relay

DragonForce ransomware operators deployed a novel Go-based backdoor called Backdoor.Turn that abuses Microsoft Teams TURN relay infrastructure to hide C2 traffic as legitimate Teams communications. The attack chain involves SQL/MSSQL server exploitation for initial access, DLL sideloading via VirtualBox/DbgView executables, multiple BYOVD techniques for defense evasion including a novel exploit of a Huawei driver, and ultimately DragonForce ransomware deployment. The group demonstrated exceptional sophistication with custom tooling and stealth techniques that evade standard network monitoring.