Google Cloud unauthorized service account activity

gcp

Classification:

compliance

Tactic:

TA0001-initial-access

Technique:

T1078-valid-accounts

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Goal

Detect when there is unauthorized activity by a service account in GCP.

Strategy

Monitor Google Cloud logs and detect when a service account makes an API request and the request returns the status code equal to 7 within the log attribute @data.protoPayload.status.code. The status code 7 indicates the service account did not have permission to make the API call.

Triage and response

  1. Investigate the service account:{{@usr.id}} that made the unauthorized calls and confirm if there is a misconfiguration in IAM permissions or if an attacker compromised the service account.
  2. If unauthorized, revoke access of compromised service account and rotate credentials.

Changelog

22 June 2022 - Updated query, rule case and triage.