The rule 'GCP iam.roles.update Privilege Escalation' identifies potential privilege escalation actions occurring in Google Cloud Platform (GCP) environments. Specifically, it focuses on the scenario where a user is granted a custom IAM role, which allows the user to update the ‘includedPermissions’ associated with that role via the 'iam.roles.update' permission. This capability can permit the user to elevate their privileges by adding any desired permissions to the role they already possess, thereby accessing resources and actions that they typically would not be able to perform. The detection targets audit logs from GCP, specifically monitoring for instances where users who already have custom roles utilize their permissions for role updates, indicating potential unauthorized access or escalation of privileges. It emphasizes the importance of adhering to the principle of least privilege and maintaining strict IAM configurations within GCP environments to prevent exploitation of these capabilities. Furthermore, it proposes validation steps for IT personnel to assess whether such activities were authorized and necessary, thereby serving as a critical alert for compliance and security oversight.