AWS Certified Advanced Networking – Specialty (ANS-C01) — Question 138

A company recently implemented a security policy that prohibits developers from launching VPC network infrastructure. The policy states that any time a NAT gateway is launched in a VPC, the company's network security team must immediately receive an alert to terminate the NAT gateway. The network security team needs to implement a solution that can be deployed across AWS accounts with the least possible administrative overhead. The solution also must provide the network security team with a simple way to view compliance history.

Which solution will meet these requirements?

Answer options

• A. Develop a script that programmatically checks for NAT gateways in an AWS account, sends an email alert, and terminates the NAT gateway if a NAT gateway is detected. Deploy the script on an Amazon EC2 instance in each account. Use a cron job to run the script every 5 minutes. Log the results of the checks to an Amazon RDS for MySQL database.
• B. Create an AWS Lambda function that programmatically checks for NAT gateways in an AWS account, sends an email alert, and terminates the NAT gateway if a NAT gateway is detected. Deploy the Lambda function to each account by using AWS Serverless Application Model (AWS SAM) templates. Store the results of the checks on an Amazon OpenSearch Service cluster in each account.
• C. Enable Amazon GuardDuty. Create an Amazon EventBridge rule for the Behavior:EC2/NATGatewayCreation GuardDuty finding type. Configure the rule to invoke an AWS Step Functions state machine to send an email alert and terminate a NAT gateway if a NAT gateway is detected. Store the runtime log as a text file in an Amazon S3 bucket.
• D. Create a custom AWS Config rule that checks for NAT gateways in an AWS account. Configure the AWS Config rule to perform an AWS Systems Manager Automation remediation action to send an email alert and terminate the NAT gateway if a NAT gateway is detected. Deploy the AWS Config rule and the Systems Manager runbooks to each account by using AWS CloudFormation StackSets

Correct answer: D

Explanation

The correct answer is D because it utilizes AWS Config, which is designed for compliance tracking and can automate the remediation process, thereby minimizing administrative overhead. Options A and B require manual deployment and maintenance of scripts or Lambda functions in each account, which increases overhead. Option C relies on GuardDuty findings, which may not provide the same level of compliance tracking as AWS Config.