Suspicious Sign-In via Legacy Authentication Protocol (via signinlogs)

ATT&CK techniques

Initial Access → Defense Evasion

Recon
Resource Dev
Initial Access
- T1078.004Cloud Accounts
Execution
Persistence
- T1078.004Cloud Accounts
Priv Esc
- T1078.004Cloud Accounts
Defense Evasion
- T1078.004Cloud Accounts
Cred Access
Discovery
Lateral Movement
Collection
C2
Exfiltration
Impact

What it detects

This rule detects successful Azure AD sign-ins over legacy authentication clients such as IMAP, POP, SMTP or other basic-auth endpoints, which cannot enforce multifactor authentication and are targeted to bypass conditional-access controls. Legacy-auth abuse is tracked in the Red Canary Threat Detection Report cloud coverage. Detecting these sign-ins surfaces an MFA-evading access path.

Reporting behind it

Related detections9 linkedT1078.004 — drag to rearrange

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Suspicious Sign-In via Legacy Authentication Protocol (via signinlogs)

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.

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