abnormal-security-account-takeover

# Abnormal Security Account Takeover Detection ## Overview Abnormal Security's Account Takeover Protection monitors sign-in activity and mailbox behavior to detect compromised internal accounts. By analyzing user behavior patterns, device fingerprints, sign-in locations, and mailbox rule changes, Abnormal identifies accounts that have been taken over by attackers. This skill covers ATO case management, investigation workflows, and remediation actions. ## Anti-triggers - **Actually resetting the password or revoking the sessions** — Abnormal detects the compromise; the identity change happens in the M365 tenant. Use `cipp-users`. - **Actually deleting the malicious inbox rule or forwarding address** — use `Microsoft 365 Mailboxes`. - **A malicious email that has not compromised anyone** — inbound attack detection is `Abnormal Security Threats`. - **The compromised mailbox belongs to a supplier, not your customer** — external senders are scored separately; use `Abnormal Security Vendors`. - **Abuse-mailbox cases** — despite the shared `caseId` vocabulary those are user-reported email submissions; use `Abnormal Security Cases`. ## Account Takeover Indicators | Indicator | Description | Risk Level | |-----------|-------------|------------| | **Impossible Travel** | Sign-ins from geographically distant locations in short time | High | | **Unusual Sign-in Location** | Sign-in from a country or region not seen before | Medium | | **New Device** | Sign-in from an ...