Suspicious Entra ID Application Consent Failure Indicating Unauthorized OAuth Grant Attempt (via azure)

ATT&CK techniques

Persistence → Priv Esc

Recon
Resource Dev
Initial Access
Execution
Persistence
- T1098.002Additional Email Delegate Permissions
Priv Esc
- T1098.002Additional Email Delegate Permissions
Defense Evasion
Cred Access
Discovery
Lateral Movement
Collection
C2
Exfiltration
Impact

What it detects

This rule detects Entra ID sign-in failures carrying error codes 65001 and 90095 which represent an unapproved application consent attempt and a denied admin-consent request. Red Canary observed adversaries triggering these consent errors while trying to authorize rogue OAuth applications for mailbox access in business email compromise schemes, so a cluster of these failures can reveal an in-progress service principal abuse attempt.

Reporting behind it

Related detections5 linkedT1098.002 — drag to rearrange

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

Suspicious ApplicationImpersonation Role Assigned to Mailbox Principal (via m365)

Malicious Consent to Known Traitorware Mail Clients via Azure AD

Malicious OAuth Application Granted Full Mailbox and EWS Permissions (via m365)

Suspicious OAuth Consent Grant to Mail Access Permissions via Azure AD

Suspicious Entra ID Application Consent Failure Indicating Unauthorized OAuth Grant Attempt (via azure)

Pivot detection · T1098.002 · 5 related

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

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