mediummultiple choiceObjective-mapped

A company has an S3 bucket containing confidential data. The security team wants to ensure that the bucket is never publicly accessible, even if a bucket policy or ACL is incorrectly set to allow public access. Which S3 feature should the developer enable?

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A company has an S3 bucket containing confidential data. The security team wants to ensure that the bucket is never publicly accessible, even if a bucket policy or ACL is incorrectly set to allow public access. Which S3 feature should the developer enable?

Answer choices

Why each option matters

Good practice is not just finding the correct option. The wrong answers often show the exact trap the exam wants you to fall into.

A

Distractor review

Enable S3 Transfer Acceleration to ensure faster uploads.

Transfer Acceleration is used to speed up uploads over long distances, not to control public access. It does not affect bucket permissions.

B

Best answer

Enable S3 Block Public Access (bucket-level).

S3 Block Public Access provides an additional layer of security that prevents any public access, even if a bucket policy or ACL inadvertently allows it. It is the recommended way to ensure a bucket is never public.

C

Distractor review

Enable S3 Server Access Logging to monitor access.

Server Access Logging provides detailed access logs but does not block public access. It is a monitoring tool, not a preventive control.

D

Distractor review

Enable S3 Object Lock to prevent objects from being deleted.

Object Lock helps prevent objects from being deleted or overwritten for a specified period. It does not address public access concerns.

Common exam trap

Common exam trap: ACLs stop at the first match

ACLs are processed top to bottom. The first matching entry wins, and an implicit deny usually exists at the end.

Technical deep dive

How to think about this question

ACL questions test precision: source, destination, protocol, port and direction. A generally correct ACL can still fail if it is applied on the wrong interface or in the wrong direction.

KKey Concepts to Remember

  • Standard ACLs match source addresses.
  • Extended ACLs can match source, destination, protocol and ports.
  • The first matching ACL entry is used.
  • There is usually an implicit deny at the end.

TExam Day Tips

  • Check inbound versus outbound direction.
  • Read the ACL from top to bottom.
  • Look for a broader permit or deny above the intended line.

Related practice questions

Related DVA-C02 practice-question pages

Use these pages to review the topic behind this question. This is how one missed question becomes focused revision.

More questions from this exam

Keep practising from the same exam bank, or move into a focused topic page if this question exposed a weak area.

Question 1

A developer is building a REST API using Amazon API Gateway that will serve static content from an Amazon S3 bucket. The API should cache responses for frequently accessed objects to reduce latency. Which API Gateway feature should the developer enable?

Question 2

A developer is running a web application on multiple Amazon EC2 instances behind an Application Load Balancer (ALB). The application needs to store user session state that must be available across all instances. The session data is small and temporary but must survive individual instance failures. Which AWS service should the developer use to store this session state?

Question 3

A developer has an AWS Lambda function that processes messages from an Amazon SQS standard queue. The function is idempotent and currently has a batch size of 10. The developer wants to increase throughput and increases the batch size to 100. After the change, CloudWatch metrics show a significant increase in throttles and the queue backlog is growing. The function's reserved concurrency is set to 10. What is the most effective action to resolve the throttling and improve throughput?

Question 4

A developer is managing an application running on Amazon EC2 instances behind an Application Load Balancer. Users report that the application becomes unresponsive after several hours, and restarting the instance temporarily fixes the issue. The developer suspects a memory leak but cannot add custom instrumentation. Which AWS service can collect memory utilization metrics and help identify the memory leak with minimal configuration?

Question 5

A developer is building a serverless web application using AWS Lambda and Amazon DynamoDB. The application needs to perform complex aggregations on data stored in DynamoDB. Which AWS service should the developer use to perform these aggregations efficiently without reading all the data into Lambda?

Question 6

A developer has an Amazon S3 bucket containing private user documents. The application must generate a time-limited URL for users to download their own documents without requiring the users to have AWS credentials. Which solution should the developer use?

FAQ

Questions learners often ask

What does this DVA-C02 question test?

Standard ACLs match source addresses.

What is the correct answer to this question?

The correct answer is: Enable S3 Block Public Access (bucket-level). — S3 Block Public Access at the bucket level provides a strong safeguard that overrides any policies or ACLs that might grant public access. It ensures that the bucket remains private regardless of other configurations. Other options like Transfer Acceleration, Server Access Logging, and Object Lock serve different purposes.

What should I do if I get this DVA-C02 question wrong?

Then try more questions from the same exam bank and focus on understanding why the wrong options are tempting.

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