Cross‑tenant helpdesk impersonation and exfiltration
🔐 Microsoft Defender Security Research outlines a human-operated intrusion playbook where attackers abuse cross-tenant Microsoft Teams collaboration to impersonate IT/helpdesk staff and socially engineer users into granting remote assistance. With user consent, adversaries gain interactive access via Quick Assist or similar tools, then execute attacker modules by side-loading them into trusted vendor-signed applications. The chain leverages native administrative protocols such as WinRM and commercial RMM tooling to move laterally and stage sensitive business data for exfiltration. Microsoft Defender provides correlated identity, endpoint, and collaboration telemetry to surface and disrupt this pathway.
