Rule: S3 buckets should prohibit public read access
Ensure S3 buckets restrict public read access for compliance
| Rule | S3 buckets should prohibit public read access |
| Framework | NIST 800-53 Revision 5 |
| Severity | ✔ Medium |
Rule Description
This rule ensures that all S3 buckets within the organization prohibit public read access, in accordance with the security controls outlined in the NIST 800-53 Revision 5 framework. Public read access can lead to unauthorized exposure of sensitive data, posing a security risk for the organization.
Remediation Steps
To remediate this rule and implement the necessary measures to prohibit public read access, follow the step-by-step guide provided below:
Step 1: Identify S3 Buckets
- 1.Login to the AWS Management Console.
- 2.Navigate to the Amazon S3 service.
Step 2: Review Bucket Permissions
- 1.For each S3 bucket, click on the bucket name to access its details.
- 2.Select the "Permissions" tab.
- 3.Review the "Access control list (ACL)" and "Bucket policy" sections to ensure that no public read access is allowed.
Step 3: Adjust Access Control List (ACL) Permissions
- 1.If any public access is found in the ACL section:
- Click on the "Access control list (ACL)" button.
- Remove any "AllUsers" or "AuthenticatedUsers" entries that allow "READ" access.
- Save the changes.
Step 4: Adjust Bucket Policy
- 1.If any public access is found in the Bucket Policy section:
- Click on the "Bucket policy" button.
- Modify the policy to deny public read access to the bucket.
- Make sure to specify the ARN (Amazon Resource Name) of the bucket in the policy.
- Save the changes.
Step 5: Repeat for all S3 Buckets
- 1.Repeat steps 2-4 for all S3 buckets in your AWS account.
Compliance Verification
To verify the compliance of the S3 buckets with the rule and ensure that public read access is prohibited, follow the steps below:
- 1.Open the AWS Management Console.
- 2.Navigate to the Amazon S3 service.
- 3.Review the permissions settings for each bucket.
- 4.Ensure that there are no "AllUsers" or "AuthenticatedUsers" entries with "READ" access in the ACL or bucket policy.
- 5.Confirm that all S3 buckets have been remediated and prohibit public read access.
Troubleshooting Steps
If you encounter issues while implementing the remediation steps or face any errors, consider the following troubleshooting steps:
- 1.Ensure that you have sufficient permissions to modify ACL and bucket policies.
- 2.Double-check the ACL and bucket policy rules to make sure they are correctly modified to prohibit public read access.
- 3.Verify that the correct ARN of the bucket is used in the bucket policy.
- 4.Check for any conflicting policies or permissions that may be overriding the intended changes.
- 5.If the issue persists, consult AWS support or refer to the official AWS documentation for further assistance.
Additional Considerations
- Regularly review and audit S3 bucket permissions and policies to maintain compliance with the rule.
- Implement an automatic remediation process using AWS Lambda or other automation tools to ensure ongoing compliance.
- Educate and train employees to avoid accidental exposure of S3 buckets by enabling public read access.
- Consider implementing an AWS Config rule to monitor and enforce the prohibition of public read access for S3 buckets.
Note: Remember to customize the remediation steps and verification process based on your specific AWS environment.