The Decoy S3 Accessed detection rule identifies suspicious access patterns to a decoy S3 bucket that has been intentionally set up to detect unauthorized or unintended access within an AWS environment. The detection relies on monitoring API calls made to the specific S3 bucket designated as a decoy resource. If a user accesses this bucket, it could indicate potentially malicious behavior, suggesting the user may not have legitimate access to sensitive data. The rule effectively uses AWS Security Hub findings and leverages the AWS API call logs to flag such access events. The detection is designed to trigger when an event is recorded with the action 'GetObject' targeting the defined decoy S3 bucket, and it remains vigilant for any external remote IP addresses accessing the bucket that do not align with expected behavior.