Breaking Down the Microsoft Entra ID Actor Token Vulnerability: The Perfect Crime in the Cloud

**Executive summary:** A critical design flaw in Microsoft Entra ID’s handling of Actor tokens enabled attackers to craft forged tokens that impersonate any user (including Global Administrators) across any tenant, bypassing MFA, Conditional Access, and producing no direct logs; Microsoft patched the issue, but defenders must hunt for secondary signs of compromise (privilege changes, service principals, mailbox rules, etc.) because the initial exploitation leaves no audit trail.