Amazon Web Services Updated DVA-C02 Exam Questions and Answers by keyaan

The EC2 instances are in private subnets with no public internet access, yet the CloudWatch agent must publish metrics to Amazon CloudWatch. To send metrics, the instances need: (1) network connectivity to CloudWatch APIs, and (2) IAM permissions that allow the agent to publish metrics and logs.

The most secure approach is to avoid opening outbound internet access via a NAT gateway (which increases the network attack surface) and instead use AWS PrivateLink through a VPC interface endpoint for CloudWatch. An interface endpoint provides private connectivity from the VPC to CloudWatch without traversing the public internet.

On the permissions side, AWS provides the managed IAM policy CloudWatchAgentServerPolicy, which is intended for the CloudWatch agent running on servers to publish metrics/logs. Attaching this policy to the EC2 instance profile role provides the needed permissions while keeping scope appropriate (unlike an admin policy).

Why the other options are not best:

A uses CloudWatchAgentAdminPolicy (broader permissions than needed) and a NAT gateway (public internet path). That is not “most secure.”

B is irrelevant here because the agent is already installed and running; the issue is publishing connectivity/permissions.

D grants read-only access, which cannot publish metrics, so it cannot fix the issue.

Therefore, attach CloudWatchAgentServerPolicy to the instance role and create a VPC interface endpoint for CloudWatch.

Why Option D is Correct:When using a container-based AWS Lambda function, you are responsible for updating the base image for runtime patches. Rebuilding the container with the latest Node.js patch version ensures the function is updated with the required security patches. Publishing a new version of the Lambda function makes the updated image available for use.

Why Other Options are Incorrect:

Option A: The runtime update mode applies to functions using AWS-managed runtimes, not container-based runtimes.

Option B: Redeploying the same version of the Lambda function does not apply the security patch.

Option C: Rebuilding with the AWS OS base image does not guarantee that the latest Node.js patch version is included.

AWS Documentation References:

Lambda Function Container Images

Node.js Updates in AWS Lambda

“Encryption in transit” for S3 means requiring requests to use HTTPS (TLS) rather than HTTP. AWS provides a standard policy condition key, aws:SecureTransport, that evaluates to true when the request is made over SSL/TLS and false when it is not. To enforce TLS for all cross-account GetObject requests, the most reliable control point is the S3 bucket resource-based policy, because the bucket is the resource being accessed and the bucket owner can enforce conditions regardless of which external account is calling.

Option A is the established pattern: add an explicit Deny statement in the bucket policy that denies all S3 actions (or at least s3:GetObject) when aws:SecureTransport is false. An explicit deny overrides any allows, ensuring that even if another account’s IAM policy allows access, the request will still be blocked if it is not using HTTPS.

Option B is backwards because it would allow insecure transport rather than deny it.

Option C is weaker because you cannot reliably enforce policies in other accounts (and principals could change roles or permissions). The bucket owner should enforce transport security at the bucket level.

Option D is not the right layer: the KMS key policy controls key usage, but the S3 GetObject transport requirement is best enforced by the S3 bucket policy. Also, S3 access can be denied before KMS is even involved.

Therefore, enforce HTTPS by adding a bucket policy Deny when aws:SecureTransport is false.