Rule: S3 Public Access Should be Blocked at Account Level
This rule focuses on blocking S3 public access at the account level for enhanced security measures.
| Rule | S3 public access should be blocked at account level |
| Framework | FedRAMP Moderate Revision 4 |
| Severity | ✔ Medium |
Rule Description
S3 public access should be blocked at the account level for FedRAMP Moderate Revision 4.
This rule ensures that S3 buckets within the AWS account are configured to prevent public access. Publicly accessible S3 buckets can pose security risks, as they may allow unauthorized access to sensitive data. By blocking public access at the account level, this rule helps to ensure compliance with the security requirements outlined in FedRAMP Moderate Revision 4.
Troubleshooting Steps
If public access to S3 buckets is not blocked at the account level, follow these troubleshooting steps:
- 1.
Verify S3 bucket policies: Check the bucket policies of all S3 buckets within the AWS account to ensure that there are no policies allowing public access. If any such policies are found, they need to be modified or removed.
- 2.
Inspect bucket ACLs: Review the Access Control Lists (ACLs) of the S3 buckets to confirm that no ACLs are granting public read/write access. If any ACLs allow public access, they should be updated to restrict access to authorized users only.
- 3.
Check bucket-level public access settings: Examine the bucket-level settings for each S3 bucket and ensure that the "Block all public access" option is enabled. This setting restricts access to objects within the buckets, preventing any public access.
- 4.
Review cross-account access: Verify that any cross-account access to the S3 buckets is properly configured and secured. Ensure that only authorized accounts have access and that public access is not allowed.
- 5.
Monitor access logs: Enable S3 access logs for all buckets and regularly monitor them for any suspicious activity that may indicate public access. Investigate and address any identified security issues promptly.
Necessary Code
No specific code snippets are required for this rule.
Step-by-Step Guide for Remediation
To block S3 public access at the account level, follow these steps:
- 1.
Log in to the AWS Management Console.
- 2.
Navigate to the Amazon S3 service.
- 3.
Select each bucket one by one.
- 4.
Review the bucket policies of each bucket and ensure that no policy allows public access.
- 5.
Inspect the ACLs of each bucket and modify any ACL that grants public read/write access. Restrict access to authorized users only.
- 6.
In the bucket settings, enable the "Block all public access" option.
- 7.
Repeat steps 3-6 for all S3 buckets within the AWS account.
- 8.
Double-check the cross-account access settings to ensure that only authorized accounts have access to the buckets.
- 9.
Enable S3 access logs for all buckets and configure monitoring for any suspicious activity.
- 10.
Regularly review and monitor access logs to promptly address any potential security issues.
By following these steps, you can ensure that S3 public access is blocked at the account level and comply with the requirements of FedRAMP Moderate Revision 4.