Detection rules › Sigma
Google Workspace Out Of Domain Email Forwarding
Detects automatic email forwarding to external domains in Google Workspace, which may indicate data leakage or misuse.
Known false positives
- Legitimate forwarding
MITRE ATT&CK coverage
| Tactic | Techniques |
|---|---|
| Collection |
Telemetry coverage
Rule body
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
Stages and Predicates
Stage 0: condition
selectionStage 1: selection
selection:
protoPayload.serviceName: 'login.googleapis.com'
protoPayload.metadata.event.eventName: 'email_forwarding_out_of_domain'
Indicators
These rows show field, operator, and value matches.
| Field | Kind | Values | Search |
|---|---|---|---|
protoPayload.metadata.event.eventName | eq |
| field:"gcp::metadata_event_name" kind:eq value:"email_forwarding_out_of_domain" |
protoPayload.serviceName | eq |
| field:"gcp::service_name" kind:eq value:"login.googleapis.com" |