This rule detects the use of the `iam.serviceAccounts.signBlob` permission in Google Cloud Platform (GCP), which allows a service account to sign arbitrary payloads. The rule identifies suspicious activity by monitoring the corresponding GCP Audit Logs for instances where this permission is granted or denied, indicating potential privilege escalation in the system. Successful use of this permission could lead to generating signed tokens for accessing sensitive resources. The rule is activated when logs indicate that an unauthorized service account attempts to invoke the `SignJwt` method with its service account. This serves as a critical indicator of abuse or misconfiguration within the identity management framework of GCP.