Question 1hardmultiple choice
Full question →hardmultiple choiceObjective-mapped
A developer needs to grant read-only access to objects in an S3 bucket (in Account A) to an IAM role in Account B. The bucket uses server-side encryption with AWS KMS (SSE-KMS) using a customer managed key (CMK) in Account A. Which of the following is REQUIRED for the cross-account access to succeed?
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
Best answer
The S3 bucket policy in Account A grants s3:GetObject to the IAM role in Account B, the KMS key policy in Account A grants kms:Decrypt to the IAM role in Account B, and the IAM role in Account B has a trust policy allowing the IAM user to assume it.
All three policies are required: the bucket policy for S3 access, the KMS key policy for decryption permissions, and the trust policy in Account B to allow the IAM user to assume the role.
B
Distractor review
The S3 bucket policy in Account A grants s3:GetObject to the IAM role in Account B, and the IAM role in Account B has a trust policy allowing the IAM user to assume it. No KMS key policy is needed because the role can use the key via IAM policies.
For cross-account KMS operations, IAM policies alone are insufficient. The KMS key policy must explicitly grant access to principals from another account. IAM policies in Account A cannot grant access to principals in Account B.
C
Distractor review
The S3 bucket policy in Account A grants s3:GetObject to the IAM user in Account B, and the IAM user's IAM policy grants s3:GetObject.
You cannot grant direct access to an IAM user in another account via a bucket policy; you must use a role. Also, the KMS key policy is missing.
D
Distractor review
The S3 bucket uses SSE-C, so the developer must provide the encryption key in the request. No KMS key policy is needed.
The scenario specifies SSE-KMS, not SSE-C. For SSE-C, no key policy is needed, but cross-account bucket policy still required. However, SSE-C is not used here.
Common exam trap
Common exam trap: answer the scenario, not the keyword
Many certification questions include familiar terms but test a specific constraint. Read the exact wording before choosing an answer that is generally true but wrong for this case.
Technical deep dive
How to think about this question
This question should be treated as a scenario, not a definition check. Identify the problem, the constraint and the best action. Then compare each option against those facts.
KKey Concepts to Remember
- Read the scenario before looking for a memorised answer.
- Find the constraint that changes the correct option.
- Eliminate answers that are true in general but not in this case.
- Use explanations to understand the rule behind the answer.
TExam Day Tips
- Underline the problem statement mentally.
- Watch for words such as best, first, most likely and least administrative effort.
- Review why wrong options are wrong, not only why the correct option is correct.
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?
Read the scenario before looking for a memorised answer.
What is the correct answer to this question?
The correct answer is: The S3 bucket policy in Account A grants s3:GetObject to the IAM role in Account B, the KMS key policy in Account A grants kms:Decrypt to the IAM role in Account B, and the IAM role in Account B has a trust policy allowing the IAM user to assume it. — For cross-account access to S3 objects encrypted with SSE-KMS, three policies must allow the operation: the S3 bucket policy in Account A must grant s3:GetObject to the IAM role in Account B; the KMS key policy in Account A must grant kms:Decrypt (and kms:GenerateDataKey if uploading) to the IAM role in Account B; and the IAM role's trust policy in Account B must allow the role to be assumed. Option B only mentions bucket policy and IAM role, missing the KMS key policy. Option C is incorrect because the IAM user's permissions in Account A are not relevant. Option D is incorrect because SSE-C is not used here. The key policy must explicitly grant the role in Account B access to the KMS key.
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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