GCP Google Workspace: Alert on Suspicious Login Classifications

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 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

Related detections9 linkedT1078.004 — drag to rearrange

Suspicious Okta SSO Access to Many Applications in Short Window

Suspicious Microsoft Entra Device Code Authentication Flow

Suspicious M365 Password Spraying via Azure PowerShell AppId from Quad7 Botnet

Suspicious AWS Instance Access or Export via SSH Key or Export Task

Suspicious Azure OpenAI Model Enumeration and Deployment Creation (via azure)

Suspicious Azure Cognitive Services Account Key Enumeration via ListKeys (via azure)

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

Suspicious AWS API Call from TruffleHog Credential Scanner User Agent

Suspicious Compute Instance Metadata Modification in GCP

GCP Google Workspace: Alert on Suspicious Login Classifications

Pivot detection · T1078.004 · 9 related

Changelog

v6

v6
Candidate ingested via manual entry.2026-09-24
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: Alert on Suspicious Login Classifications"
id: 7478c96e-af6d-4f54-a5db-ca9d4d758f1a
status: experimental
description: 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.
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
modified: 2026-09-14
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

Convert

This rule as a query you can run. Uses no unlock credit.

SplunkSPL