Malicious Business Email Compromise OAuth Application Sign-In via Entra ID Service Principal (via azure)

PremiumReviewedSigma · High · v1
Product
azure
Service
signinlogs
Author
HuntRule
Published
2026-10-23
Updated
2026-10-23

ATT&CK techniques

Initial Access → Defense Evasion
  1. Recon

  2. Resource Dev

  3. Execution

  4. Cred Access

  5. Discovery

  6. Lateral Movement

  7. Collection

  8. C2

  9. Exfiltration

  10. Impact

What it detects

This rule detects Entra ID sign-ins tied to the PerfectData Software and eM Client OAuth application identifiers that Red Canary observed adversaries abusing to gain persistent mailbox access during business email compromise schemes. Attackers consent these third-party mail applications into a compromised tenant so they can read and exfiltrate mail through issued tokens without the victim password, making any sign-in with these application IDs a strong compromise indicator.

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Malicious Business Email Compromise OAuth Application Sign-In via Entra ID Service Principal (via azure)
Pivot detection · T1078.004 · 9 related

Detection content is published as a reviewed draft. Tune thresholds and exclusions against your own telemetry before enabling this rule for alerting.