Google Workspace Out Of Domain Email Forwarding

title: Google Workspace Out Of Domain Email Forwarding
id: 2a0bb2dd-eb5f-4517-8cb9-404f8ba764a5
status: experimental
description: Detects automatic email forwarding to external domains in Google Workspace, which may indicate data leakage or misuse.
references:
    - https://developers.google.com/workspace/admin/reports/v1/appendix/activity/login#email_forwarding_out_of_domain
author: Tom kluter
date: 2026-04-28
tags:
    - attack.t1114.003
    - attack.collection
logsource:
    product: gcp
    service: google_workspace.login
detection:
    selection:
        protoPayload.serviceName: 'login.googleapis.com'
        protoPayload.metadata.event.eventName: 'email_forwarding_out_of_domain'
    condition: selection
falsepositives:
    - Legitimate forwarding
level: medium