GCP Google Workspace Suspicious Login Events (Google Classified)

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 flags Google Workspace login audit events where Google has classified the login as suspicious. Such activity can indicate attacker attempts to access accounts using less secure authentication methods or automated/programmatic login patterns. It relies on GCP audit log telemetry from login.googleapis.com and matches specific eventName values in protoPayload.metadata.event.eventName.

Reporting behind it

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GCP Google Workspace Suspicious Login Events (Google Classified)

Pivot detection · T1078.004 · 9 related

Changelog

v4

v4
Candidate ingested via manual entry.2026-07-31
v3
Candidate ingested via manual entry.2026-07-31
v2
Candidate ingested via manual entry.2026-07-31
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.

google-workspace-logins-marked-suspicious-by-google-gcp-38360161

title: GCP Google Workspace Suspicious Login Events (Google Classified)
id: 7478c96e-af6d-4f54-a5db-ca9d4d758f1a
status: experimental
description: This rule flags Google Workspace login audit events where Google has classified the login as suspicious. Such activity can indicate attacker attempts to access accounts using less secure authentication methods or automated/programmatic login patterns. It relies on GCP audit log telemetry from login.googleapis.com and matches specific eventName values in protoPayload.metadata.event.eventName.
references:
  - https://cloud.google.com/logging/docs/audit/gsuite-audit-logging
  - https://cloud.google.com/logging/docs/audit/understanding-audit-logs
  - https://developers.google.com/workspace/admin/reports/v1/appendix/activity/login#suspicious_login
  - https://developers.google.com/workspace/admin/reports/v1/appendix/activity/login#suspicious_login_less_secure_app
  - https://developers.google.com/workspace/admin/reports/v1/appendix/activity/login#suspicious_programmatic_login
  - https://github.com/SigmaHQ/sigma/blob/master/rules/cloud/gcp/gworkspace/login/gcp_gworkspace_suspicious_login.yml
author: Tom Kluter, Huntrule Team
date: 2026-04-28
tags:
  - attack.initial-access
  - attack.privilege-escalation
  - attack.persistence
  - attack.stealth
  - attack.t1078.004
logsource:
  product: gcp
  service: google_workspace.login
detection:
  selection:
    protoPayload.Servicename: login.googleapis.com
    protoPayload.metadata.event.eventName:
      - suspicious_login_less_secure_app
      - suspicious_login
      - suspicious_programmatic_login
  condition: selection
falsepositives:
  - Legitimate logins
level: medium
license: DRL-1.1
related:
  - id: 38360161-76c4-4283-842e-efcf997dafc8
    type: derived

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