This check identifies AWS KMS keys with overly permissive policies that grant full access to all AWS services or users. KMS keys with policies allowing kms:* actions to all principals (AWS:*) create a significant security risk, potentially allowing unauthorized users to access, modify, or delete encrypted data across your AWS environment.
Vulnerable policies typically include a statement with Effect:Allow, Principal:{"AWS":"*"}, and Action:["kms:*"], as shown in this insecure example:
Secure your KMS keys by using least privilege principless—restrict access to specific IAM roles/users, limit actions to only those needed, and use explicit Deny statements where appropriate as shown in the following example: