Ensure that the content permissions of your Amazon S3 buckets can't be viewed by authenticated users (i.e. signed AWS accounts or IAM users) in order to protect your S3 data against unauthorized access. An Amazon S3 bucket that grants READ_ACP (VIEW) access to signed AWS users can allow any authenticated user to examine your Access Control List (ACL) configuration and find permission vulnerabilities.
This rule can help you with the following compliance standards:
For further details on compliance standards supported by Conformity, see here.
This rule can help you work with the AWS Well-Architected Framework.
This rule resolution is part of the Conformity Security & Compliance tool for AWS.
Granting authenticated READ_ACP access to your Amazon S3 buckets can enable the unauthorized users to see who controls your S3 objects and how. Malicious users can use this information to find S3 objects with misconfigured permissions and try probing techniques to facilitate access to your Amazon S3 data. To meet security and compliance requirements, avoid granting READ_ACP (VIEW) permissions to the "Authenticated users group (anyone with an AWS account)" grantee in production.
To determine if your Amazon S3 buckets allow READ_ACP access to AWS authenticated users, perform the following operations:
Remediation / Resolution
To remove authenticated READ_ACP access permissions from your Amazon S3 bucket ACL, perform the following operations:Note: An S3 bucket can be deemed compliant if implements either "AccessControl": "Private" or sets the "PublicAccessBlockConfiguration" feature options to true. The following CloudFormation template uses both for added security.
- AWS Documentation
- Amazon S3 FAQs
- Access Control List (ACL) Overview
- Configuring ACLs
- Identity and access management in Amazon S3
- CloudFormation Documentation
- Access Control
- Terraform Documentation
- AWS Provider
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You are auditing:
S3 Bucket Authenticated Users 'READ_ACP' Access
Risk level: Very High