M365EXO-034: AI-based phishing detection in use (MS.EXO.11.3)
- Platform
- Entra ID / M365
- Category
- Advanced Threat Protection
- Severity
- Medium
- Zero Trust pillar
- Applications & Workloads (weight 1)
- Golden fixtures
- 3
- Branch coverage
- Observed: fixtures prove the verdicts they exercise
- Provenance
- baseline
What it checks
SCuBA MS.EXO.11.3 recommends an AI-based phishing detection tool comparable to EOP Mailbox Intelligence. Mailbox intelligence builds a model of a user's normal correspondents to detect anomalous senders that rule-based filters miss. Without an AI-based layer, novel or highly targeted phishing is more likely to evade detection.
Recommended value
Anti-phish policy with mailbox intelligence enabled (EnableMailboxIntelligence = True) and protection action configured
Remediation
Enable mailbox intelligence in the anti-phish policy and configure the mailbox intelligence protection action to handle detected impersonations. Apply the policy to all users. Mailbox intelligence requires a Defender for Office 365 plan; where unavailable, evaluate a comparable AI-based third-party phishing detection capability.
Fixture-proven verdicts
Every verdict below is proven by a golden fixture in the module's gating test suite. This table derives from the last green run; it cannot be edited by hand.
| Scenario | Expected verdict |
|---|---|
| clean | PASS |
| known-bad | WARN |
| throttled | Not Assessed |
Framework mappings
- NIST SP 800-53
- SI-8
- MITRE ATT&CK
- T1566