CloudFormation stack drift detection (rule)

Checks if the actual configuration of a Cloud Formation stack differs, or has drifted, from the expected configuration. A stack is considered to have drifted if one or more of its resources differ from their expected configuration. The rule and the stack are COMPLIANT when the stack drift status is IN_SYNC. The rule and the stack are NON_COMPLIANT when the stack drift status is DRIFTED. CloudFormation Stack Drift Detection