The correct answer is to add a bucket policy that restricts S3 bucket access to the VPC endpoint or the specific IP addresses of the EC2 instances. This works because the bucket policy uses condition keys like `aws:SourceVpce` or `aws:SourceIp` to enforce a network-level restriction, ensuring that only requests originating from the designated VPC endpoint or the EC2 instances’ public IPs are allowed, even if other services or accounts possess valid IAM credentials. On the AWS Certified Developer Associate DVA-C02 exam, this scenario tests your understanding of how bucket policies complement IAM roles by adding an explicit deny for all other sources—a common trap is assuming the IAM role alone is sufficient, but it does not prevent access from other authenticated entities. Remember the memory tip: “IAM says who, bucket policy says where”—the role grants the permission, but the policy locks down the network path.
DVA-C02 Security Practice Question
This DVA-C02 practice question tests your understanding of security. This is a configuration task: choose the command set that satisfies every stated requirement. Small differences — like 'secret' vs 'password' or 'transport input ssh' vs 'all' — change whether the answer is correct. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
A developer is using AWS CodePipeline to deploy a web application. The pipeline includes a source stage from CodeCommit, a build stage using CodeBuild, and a deploy stage using CodeDeploy to EC2 instances. The application stores sensitive data in an S3 bucket. The developer needs to ensure that the S3 bucket is only accessible from the EC2 instances and not from any other AWS service or account. The EC2 instances have an IAM role that allows s3:GetObject. What additional configuration is required?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Add a bucket policy that allows access only from the VPC endpoint or specific IP addresses of the EC2 instances.
Option C is correct because a bucket policy that restricts access to the S3 bucket from a specific VPC endpoint or the EC2 instances' IP addresses ensures that only requests originating from those sources are allowed. This complements the IAM role's s3:GetObject permission by adding a network-level condition, preventing other AWS services or accounts from accessing the bucket even if they have valid IAM credentials. The condition key `aws:SourceVpce` or `aws:SourceIp` in the bucket policy enforces this restriction.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✗
Use SSE-KMS encryption on the bucket.
Why it's wrong here
Encryption does not control access.
✗
Enable S3 Block Public Access on the bucket.
Why it's wrong here
Does not restrict other AWS services.
✓
Add a bucket policy that allows access only from the VPC endpoint or specific IP addresses of the EC2 instances.
Why this is correct
Restricts access to the instances.
Related concept
Read the scenario before looking for a memorised answer.
✗
Move the sensitive data to a different S3 bucket and update the application.
Why it's wrong here
Does not address the access issue.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often confuse encryption (SSE-KMS) or public access controls (Block Public Access) with network-level access restrictions, failing to realize that IAM permissions alone are insufficient to prevent access from other AWS services or accounts that have their own valid credentials.
Detailed technical explanation
How to think about this question
Under the hood, S3 bucket policies support condition keys like `aws:SourceVpce` to restrict access to requests originating from a specific VPC endpoint, or `aws:SourceIp` to limit access to specific IP ranges. This works by evaluating the policy at the service level before the request reaches the bucket, effectively creating a network-based access control layer. In real-world scenarios, this prevents data exfiltration by rogue services or compromised IAM roles that might attempt to access the bucket from outside the designated network path.
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.
TExam Day Tips
→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.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A media company stores terabytes of video archives that are accessed once a year for audit purposes. Moving these objects to a cold storage tier (Azure Archive, S3 Glacier, or Google Nearline) costs a fraction of hot storage. Questions like this test whether you understand storage tiers, access frequency tradeoffs, and retrieval latency requirements.
What to study next
Got this wrong? Here's your next step.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Security — This question tests Security — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Add a bucket policy that allows access only from the VPC endpoint or specific IP addresses of the EC2 instances. — Option C is correct because a bucket policy that restricts access to the S3 bucket from a specific VPC endpoint or the EC2 instances' IP addresses ensures that only requests originating from those sources are allowed. This complements the IAM role's s3:GetObject permission by adding a network-level condition, preventing other AWS services or accounts from accessing the bucket even if they have valid IAM credentials. The condition key `aws:SourceVpce` or `aws:SourceIp` in the bucket policy enforces this restriction.
What should I do if I get this DVA-C02 question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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