The detection rule for GCP Cloud Functions updates is designed to identify unauthorized privilege escalation attempts within Google Cloud Platform (GCP) environments. It focuses on monitoring the actions taken via the Identity and Access Management (IAM) service, which is crucial for managing user permissions and roles. The rule triggers when there is an attempt to update Cloud Functions by checking the permission 'cloudfunctions.functions.update.' If the permission is granted, it is logged as a potential privilege escalation event since it is critical to ensure that such updates are authorized. This is particularly important given that many methods of privilege escalation may circumvent the IAM service entirely. The rule operates by analyzing audit logs generated within the GCP environment, specifically looking for discrepancies that indicate unauthorized access or changes. A high severity rating underscores the importance of monitoring these actions due to the potential impact on security posture resulting from unauthorized privileges on GCP services. Furthermore, the associated runbook emphasizes the need to verify legitimate operations and maintain a principle of least privilege to mitigate these security risks effectively.