huntrule

GCP Google Workspace: Alert on Suspicious Login Classifications

Alerts on Google Workspace login audit events classified by Google as suspicious, including less secure app and programmatic login types.

FreeReviewedSigma · Medium · v6
Product
gcp
Service
google_workspace.login
Author
Tom Kluter (SigmaHQ), DRL 1.1
Published
2026-04-28
Updated
2026-09-24
AnalysisDetection

ATT&CK techniques

Initial Access → Defense Evasion

  1. Recon

  2. Resource Dev

  3. Initial Access

  4. Execution

  5. Persistence

  6. Priv Esc

  7. Defense Evasion

  8. Cred Access

  9. Discovery

  10. Lateral Movement

  11. Collection

  12. C2

  13. Exfiltration

  14. Impact

What it detects

This rule flags Google Workspace login audit events from login.googleapis.com that are explicitly classified by Google as suspicious. Attackers often use abnormal authentication patterns such as less secure clients, suspicious interactive logins, or programmatic access to evade controls. The detection relies on GCP audit log fields, matching protoPayload.serviceName and the eventName values suspicious_login, suspicious_login_less_secure_app, or suspicious_programmatic_login.

Reporting behind it

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GCP Google Workspace: Alert on Suspicious Login Classifications
Pivot detection · T1078.004 · 9 related

Changelog

v6
  1. v6
    Candidate ingested via manual entry.2026-09-24
  2. v4
    Candidate ingested via manual entry.2026-07-31
  3. v3
    Candidate ingested via manual entry.2026-07-31
  4. v2
    Candidate ingested via manual entry.2026-07-31
  5. v1
    No changelog recorded for this version.2026-07-30

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