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DragonForce Used Microsoft Teams Relays to Hide New Backdoor

The method masks command traffic inside trusted collaboration media, letting attackers remain unseen for months and making network detection much harder.

Overview

  • Researchers say attackers first gained a foothold in the victim’s network in December 2025 through an exposed or purchased SQL/MSSQL access, then used DLL sideloading to run additional payloads.
  • After months of stealthy reconnaissance and lateral movement, DragonForce deployed ransomware and then installed a Go-based backdoor tracked as Backdoor.Turn to preserve access or sell the breach.
  • Backdoor.Turn obtains anonymous Teams visitor tokens, connects through legitimate Microsoft TURN relay servers and runs a QUIC session to attacker servers so C2 traffic looks like normal Teams media traffic.
  • Defenders report the intruders used Bring-Your-Own-Vulnerable-Driver techniques against signed drivers, including exploitation of a Huawei audio driver and a malicious driver disguised as a Palo Alto component to gain kernel privileges and disable protections.
  • Broadcom’s Symantec and Carbon Black published indicators and mitigation advice in mid-June 2026 and recommend auditing TURN/QUIC telemetry, hardening exposed SQL/MSSQL services, and monitoring visitor-token use and unexpected driver loads to detect similar attacks.