The rule "AWS CloudTrail Log Created" identifies instances where an AWS CloudTrail log trail is created, which is crucial for monitoring user activity and ensuring the security of AWS environments. The presence of a new CloudTrail may indicate unauthorized activity, as adversaries can create trails to capture sensitive data or obfuscate their tracks. The rule triggers on successful creation events within a specified time frame, providing alerts that enable security teams to investigate the legitimacy of these actions. The investigation process includes reviewing related AWS CloudTrail logs, checking for unusual user activities, and ensuring compliance with change management practices. False positives can arise from legitimate administrative actions or automated processes; thus, maintaining accurate documentation is essential for differentiation. In the case of unauthorized trail creations, immediate actions should follow, such as disabling the trail, conducting audits, and tightening IAM policies.