Rule: Amazon S3 Permissions Restriction in Bucket Policies
Ensure other AWS accounts in bucket policies have restricted permissions.
| Rule | Amazon S3 permissions granted to other AWS accounts in bucket policies should be restricted |
| Framework | AWS Foundational Security Best Practices |
| Severity | ✔ High |
Rule Description
AWS recommends restricting permissions granted to other AWS accounts in Amazon S3 bucket policies to ensure proper security and adhere to AWS Foundational Security Best Practices.
Rule Explanation
Granting excessive permissions to other AWS accounts in Amazon S3 bucket policies can potentially compromise data security, increasing the risk of unauthorized access or data leaks. To mitigate this risk, it is important to follow AWS Foundational Security Best Practices and restrict permissions to only those accounts that require access.
Remediation Steps
Follow the steps below to remediate this issue and restrict permissions granted to other AWS accounts in Amazon S3 bucket policies:
Step 1: Identify the affected bucket policies
- 1.Log in to the AWS Management Console.
- 2.Open the Amazon S3 console at https://console.aws.amazon.com/s3/.
- 3.Navigate to the bucket for which you want to review the bucket policies.
Step 2: Review the bucket policies
- 1.Select the "Permissions" tab for the bucket in the Amazon S3 console.
- 2.Review the existing bucket policies under the "Access control list (ACL)" and "Bucket policy" sections.
- 3.Identify any explicit permissions granted to other AWS accounts.
Step 3: Modify the bucket policies
- 1.Determine the AWS accounts that require access to the bucket and their specific permission requirements. Ensure that these are the only accounts with access to the bucket.
- 2.Edit the bucket policies to remove any unnecessary or overly permissive access granted to other AWS accounts.
- 3.Update the bucket policy to restrict the permissions to only the necessary AWS accounts. Ensure that the policy includes only the required actions and resources.
Step 4: Verify the updated permissions
- 1.Review the modified bucket policies to ensure that they restrict permissions to the desired AWS accounts.
- 2.Test the access to the bucket from the allowed AWS accounts to confirm that they have the necessary permissions.
Troubleshooting Steps
If you encounter any issues during the remediation process, follow these troubleshooting steps:
- 1.Check for any syntax errors or typos in the updated bucket policies. Ensure that the policy is written correctly, following the AWS policy grammar.
- 2.Verify the AWS account IDs of the accounts that require access and ensure that they are correctly configured in the bucket policies.
- 3.Test the access from the allowed AWS accounts again to ensure that they have the necessary permissions. If there are any issues, review the policy and make any necessary adjustments.
Additional Considerations
- Regularly review and audit your Amazon S3 bucket policies to ensure that permissions granted to other AWS accounts are restricted to the minimum necessary.
- Consider implementing IAM Roles and cross-account access for better control over permissions and resource sharing between AWS accounts.
- Enable S3 bucket logging and configure alerts to monitor access and detect any unauthorized activities.
- Regularly monitor AWS Trusted Advisor and Security Hub findings to identify and address any security issues related to AWS S3 bucket policies.