AWS Certified Security – Specialty — Question 237

An application is running on an Amazon EC2 instance that has an IAM role attached. The IAM role provides access to an AWS Key Management Service (AWS
KMS) customer managed key and an Amazon S3 bucket.
A security engineer discovers a potential vulnerability on the EC2 instance that could result in the compromise of the sensitive data. Due to other critical operations, the security engineer cannot immediately shut down the EC2 instance for vulnerability patching.
What is the FASTEST way to prevent the sensitive data from being exposed?

Answer options

• A. Download the data from the existing S3 bucket to a new EC2 instance. Then delete the data from the S3 bucket. Re-encrypt the data with a client-based key. Upload the data to a new S3 bucket.
• B. Block access to the public range of S3 endpoint IP addresses by using a host-based firewall. Ensure that internet-bound traffic from the affected EC2 instance is routed through the host-based firewall.
• C. Revoke the IAM role's active session permissions. Update the S3 bucket policy to deny access to the IAM role. Remove the IAM role from the EC2 instance profile.
• D. Disable the current key. Create a new KMS key that the IAM role does not have access to, and re-encrypt all the data with the new key. Schedule the compromised key for deletion.

Correct answer: C

Explanation

The correct answer is C because revoking the IAM role's permissions and updating the S3 bucket policy immediately restricts access to the sensitive data, thus preventing any potential exposure. Options A and D involve complicated processes that take more time and still do not address the immediate risk on the existing EC2 instance. Option B only partially mitigates the risk by blocking external access but does not stop potential internal access to sensitive data.