Ensure that your AWS S3 buckets content cannot be listed by AWS authenticated accounts or IAM users in order to protect your S3 data against unauthorized access. An S3 bucket that allows READ (LIST) access to authenticated users will provide AWS accounts or IAM users the ability to list the objects within the bucket and use the information acquired to find objects with misconfigured ACL permissions and exploit them.
Granting authenticated “READ” access to S3 buckets can allow unauthorized users to list all the objects within the buckets and use this information to gain access to your S3 data. Cloud Conformity strongly recommends against setting READ (LIST) permission for the "Any Authenticated AWS User" ACL predefined group in production.
To determine if your S3 buckets allow READ access to AWS authenticated users, perform the following:
To remove authenticated READ access to your S3 buckets, you need to perform the following: