The Decoy Systems Manager Parameter Accessed rule is designed to detect unauthorized access to a decoy Systems Manager parameter within an AWS environment. When an actor accesses this designated decoy parameter, an alert is triggered indicating that potentially suspicious activity has occurred. This rule operates by monitoring API calls related to the decoy parameter. If an API call is made to decrypt this parameter using AWS Key Management Service (KMS), it suggests that someone may be attempting to access secretive or sensitive information. Additionally, the rule is set to check for suspicious access patterns and replicate logs for cross-referencing against known behaviors. The alerts generated help in identifying any unintended or unauthorized access attempts, facilitating timely responses to potential security breaches. Given its high severity design, it emphasizes the importance of monitoring decoy resources in cloud security operations. The rule's design incorporates deduplication periods to minimize duplicate alerts over short intervals, streamlining incident management workflows.