AWS Certified Security – Specialty — Question 160

A threat assessment has identified a risk whereby an internal employee could exfiltrate sensitive data from production host running inside AWS (Account 1). The threat was documented as follows:
Threat description: A malicious actor could upload sensitive data from Server X by configuring credentials for an AWS account (Account 2) they control and uploading data to an Amazon S3 bucket within their control.
Server X has outbound internet access configured via a proxy server. Legitimate access to S3 is required so that the application can upload encrypted files to an
S3 bucket. Server X is currently using an IAM instance role. The proxy server is not able to inspect any of the server communication due to TLS encryption.
Which of the following options will mitigate the threat? (Choose two.)

Answer options

• A. Bypass the proxy and use an S3 VPC endpoint with a policy that whitelists only certain S3 buckets within Account 1.
• B. Block outbound access to public S3 endpoints on the proxy server.
• C. Configure Network ACLs on Server X to deny access to S3 endpoints.
• D. Modify the S3 bucket policy for the legitimate bucket to allow access only from the public IP addresses associated with the application server.
• E. Remove the IAM instance role from the application server and save API access keys in a trusted and encrypted application config file.

Correct answer: A, B

Explanation

Option A is correct because using an S3 VPC endpoint allows traffic to flow directly from Server X to S3 without going through the proxy, while restricting access to specific buckets mitigates the risk of data exfiltration. Option B is also correct as blocking outbound access to public S3 endpoints prevents unauthorized uploads to external S3 buckets. The other options either do not adequately secure against the identified threat or may hinder legitimate operations without effectively addressing the risk.