Suspicious Entra Agent Service Principal Sign-In With PowerShell User Agent via Sign-In Logs

ATT&CK techniques

Defense Evasion → Lateral Movement

Recon
Resource Dev
Initial Access
Execution
Persistence
Priv Esc
Defense Evasion
- T1550.001Application Access Token
Cred Access
Discovery
Lateral Movement
- T1550.001Application Access Token
Collection
C2
Exfiltration
Impact

What it detects

This rule detects a service principal sign-in using a PowerShell user agent against Entra Agent ID identities, a pattern of automated credential misuse where an attacker authenticates as an AI agent through scripted Graph calls. Because assigned agents normally authenticate through their own runtime rather than interactive PowerShell tooling, this user agent on service principal sign-ins indicates hands-on-keyboard abuse of agent credentials.

Reporting behind it

Related detections9 linkedT1550.001 — drag to rearrange

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Suspicious AWS STS Session Token and Role Chaining Abuse via CloudTrail (via aws)

Suspicious Entra Agent Service Principal Sign-In With PowerShell User Agent via Sign-In Logs

Pivot detection · T1550.001 · 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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