Description

A GCP service account that can be assumed by a third party or is publicly assumable also has a path to escalate privileges to another service account. An external principal, or an attacker who compromises the third-party account or assumes the publicly assumable service account, can leverage privilege-escalation permissions to gain broader access within the GCP project.

Remediation

1. Review and restrict which principals can assume this service account, ensuring it is not assumable by third parties or the public. See Granting, changing, and revoking access for guidance.
2. Apply least privilege best practices for service accounts to remove unnecessary privilege-escalation permissions.