The rule `AWS.CloudTrail.EnableRegion` is designed to detect the unauthorized enabling of AWS regions within a user's account via AWS CloudTrail logs. This activity can indicate that a threat actor has compromised an account and is attempting to exploit less-monitored regions, which are often overlooked by security measures. The rule operates based on logs generated from AWS CloudTrail when an `EnableRegion` API call is made. The expected behavior is for the event to be logged with specific attributes, indicating the user identity, source, and parameters of the region being enabled. If the detection rule is triggered, it suggests a potential security incident where a region might have been activated without proper authorization. In such cases, procedures including validating permissions, revoking access, and reviewing logs in the new region are recommended. This detection aligns with MITRE ATT&CK framework under the tactic of Credential Access, particularly the technique of Credentials from Cloud Providers due to the misuse of compromised credentials.