Google's Mandiant team published a report on April 22 naming UNC6692, a previously untracked threat cluster running a high-conversion social engineering playbook against senior enterprise staff - 77% of observed targets were senior employees between March 1 and April 1, 2026. The attack opens with an email bombing burst, flooding the victim's inbox with spam to create urgency. The operator then sends a Microsoft Teams chat invite from an external account, posing as internal IT help, and offers to fix the spam problem via a link to a convincing phishing page called 'Mailbox Repair and Sync Utility v2.1.5'. The page forces Microsoft Edge via the microsoft-edge: URI scheme, harvests credentials through a fake 'Health Check' button, and downloads an AutoHotkey script from attacker-controlled AWS S3 that installs the SNOW malware family: SNOWBELT (a malicious Edge/Chromium extension disguised as 'MS Heartbeat' that holds persistence through Scheduled Tasks and a Startup-folder shortcut), SNOWGLAZE (a Python WebSocket tunneler wrapping traffic in Base64-encoded JSON), and SNOWBASIN (a Python bindshell for interactive remote control). Post-exploitation includes LSASS dumps, Pass-the-Hash lateral movement, PsExec and RDP over the SNOWGLAZE tunnel, and exfil via LimeWire.
Microsoft Threat Intelligence is warning of a surge in attacks where threat actors pose as IT or helpdesk staff in external Microsoft Teams cross-tenant chats to trick employees into granting remote access - then use legitimate tools to steal data while blending into normal IT activity. The attack chain has nine stages. First, the attacker opens an external Teams chat claiming to be internal IT addressing an account issue. They talk the target into starting a Quick Assist remote support session, giving the attacker direct control of the machine. From there they do quick recon via Command Prompt and PowerShell, drop a small payload in user-writable locations like ProgramData, and execute it through DLL side-loading using a trusted signed application (Autodesk, Adobe Reader, Windows Error Reporting, or even data loss prevention software - any binary with a valid Microsoft-trusted signature). HTTPS C2 blends into normal outbound traffic. They establish persistence via Windows Registry, then use Windows Remote Management (WinRM) to move laterally to domain controllers and high-value assets. Final stage: Rclone exfiltrates filtered data to external cloud storage. Microsoft's detection guidance is blunt - this blends into legitimate admin activity and is hard to distinguish from routine IT support.
TrustStrike Labs