UNC6508 Exfiltrated Through a Gmail Compliance Rule. The Audit Event Your Detection Uses Retires After August
A PRC-nexus actor exfiltrated years of medical and defense research by creating a single domain-level Gmail content compliance rule that silently BCC’d matching mail to an attacker Gmail account. It produced no endpoint telemetry and no user-visible forwarding setting, and the admin audit event family that authoritatively records it is mid-migration, with the legacy events retiring after August 2026.