S3 Access block should restrict public bucket to limit access

Explanation

S3 buckets should restrict public policies for the bucket. By enabling, the restrict_public_buckets, only the bucket owner and AWS Services can access if it has a public policy.

Possible Impact

Public buckets can be accessed by anyone

Suggested Resolution

Limit the access to public buckets to only the owner or AWS Services (eg; CloudFront)

Insecure Example

The following example will fail the AVD-AWS-0093 check.

---
Resources:
  BadExample:
    Properties:
      AccessControl: AuthenticatedRead
    Type: AWS::S3::Bucket

Secure Example

The following example will pass the AVD-AWS-0093 check.

---
Resources:
  GoodExample:
    Properties:
      PublicAccessBlockConfiguration:
        BlockPublicAcls: true
        BlockPublicPolicy: true
        IgnorePublicAcls: true
        RestrictPublicBuckets: true
    Type: AWS::S3::Bucket


Getting Started
Services