Rule: S3 Public Access Blocked at Account Level
Implement security measure to prevent unauthorized access to S3 buckets
| Rule | S3 public access should be blocked at account level |
| Framework | NIST 800-53 Revision 4 |
| Severity | ✔ Medium |
Rule Description
The rule mandates blocking public access at the account level for Amazon S3 to comply with the guidelines outlined in the NIST 800-53 Revision 4 security standard. This ensures that S3 buckets within the account are not publicly accessible, preventing unauthorized access to sensitive data stored in these buckets.
Troubleshooting Steps
If public access to S3 buckets is detected or reported, follow these troubleshooting steps:
- 1.
Identify the affected S3 bucket(s) by reviewing the account's S3 bucket permissions.
- 2.
Determine the source of the public access and investigate potential misconfigurations or unauthorized changes.
- 3.
Take immediate action to restrict public access to the affected bucket(s). This can be done by modifying bucket policies, access control lists (ACLs), or the associated IAM roles and policies.
- 4.
Conduct a thorough review of all S3 bucket configurations in the account to ensure the appropriate access controls are in place.
- 5.
Monitor and track any attempts to access the S3 buckets from unauthorized sources and investigate any suspicious activities.
Necessary Codes
No code changes are required for this rule. However, you may need to review and modify the bucket policies, ACLs, IAM roles, and policies associated with each S3 bucket as necessary to block public access.
Remediation Steps
Follow these step-by-step instructions to remediate the public access issue at the account level:
- 1.
Access the AWS Management Console.
- 2.
Navigate to the Amazon S3 service.
- 3.
Review the list of S3 buckets within the account.
- 4.
For each bucket that has public access enabled, perform the following steps:
a. Select the bucket and click on the "Permissions" tab.
b. Review the bucket policy to ensure it does not allow public access. If necessary, remove or modify the policy to restrict access to authorized users or resources only.
c. Review the bucket's ACL to ensure it does not grant public access. If necessary, remove or modify any ACL entries that allow public access.
d. Review the associated IAM roles and policies to ensure they do not provide unintended public access. Modify or remove any relevant roles or policies as needed.
- 5.
Repeat steps 4a-4d for all the buckets within the account.
- 6.
Once all the buckets have been reviewed and public access has been blocked, conduct additional testing to verify the changes.
- 7.
Regularly monitor and audit the account's S3 buckets to ensure ongoing compliance with the NIST 800-53 Revision 4 security standard.
Note: It is essential to involve the appropriate stakeholders, such as system administrators, security teams, and compliance officers, while implementing and validating these changes to ensure adherence to organizational guidelines and policies.