The answer is that the bucket policy itself contains a deny statement overriding the IAM role’s allow. Even though the pipeline’s service role has an explicit s3:PutObject permission on the bucket’s objects, AWS evaluates both identity-based policies (the role) and resource-based policies (the bucket policy) — and a deny in either one will win over any allow. This is a classic exam trap on the AWS Certified Solutions Architect Professional SAP-C02, testing your understanding of the policy evaluation logic: an explicit deny always takes precedence, so a seemingly permissive IAM role can still fail if the bucket policy includes a condition or principal that blocks the pipeline’s service principal. The “CodePipeline Access Denied to S3 bucket policy” scenario is a frequent distractor because candidates focus only on the role, forgetting that bucket policies are independent guardrails. Memory tip: “Deny always wins — check both sides of the policy fence.”
SAP-C02 Continuous Improvement for Existing Solutions Practice Question
This SAP-C02 practice question tests your understanding of continuous improvement for existing solutions. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. 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 company uses AWS CodePipeline to deploy a static website to an S3 bucket. The pipeline includes a source stage from GitHub and a deploy stage that syncs the S3 bucket. Recently, the deployment has been failing intermittently with the error 'Access Denied' when the pipeline tries to write to the S3 bucket. The bucket policy allows the pipeline's service role to perform s3:PutObject. The service role has the following IAM policy attached: { 'Effect': 'Allow', 'Action': 's3:PutObject', 'Resource': 'arn:aws:s3:::my-bucket/*' }. What is the MOST likely cause of the failure?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue: "most likely"
Why it matters: Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
The bucket has a bucket policy that denies the pipeline's service role.
Option A is correct. The bucket policy might deny access even if the IAM role allows it, because bucket policies are evaluated in addition to IAM policies. Option B is wrong because the pipeline uses the service role, not Git credentials. Option C is wrong because there is no mention of encryption. Option D is wrong because the error is Access Denied, not a network issue.
Key principle: ACLs process entries top to bottom and stop at the first match. Entry order and interface direction matter as much as the permit or deny statement.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✗
The S3 bucket has default encryption enabled.
Why it's wrong here
Default encryption does not cause Access Denied for PutObject.
✗
The pipeline is in a VPC without an S3 VPC endpoint.
Why it's wrong here
Access Denied is a permissions issue, not connectivity.
✗
The pipeline's source stage is not configured with Git credentials.
Why it's wrong here
Source stage uses HTTPS or OAuth, not for S3 writes.
✓
The bucket has a bucket policy that denies the pipeline's service role.
Why this is correct
An explicit deny in the bucket policy overrides the IAM allow.
Clue confirmation
The clue word "most likely" in the question point toward this answer.
Related concept
Standard ACLs match source addresses.
Common exam traps
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.
Detailed technical explanation
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.
Key takeaway
ACLs process entries top to bottom and stop at the first match. Entry order and interface direction matter as much as the permit or deny statement.
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.
Review ACL processing order, placement rules (standard near destination, extended near source), and inbound vs outbound direction. Study wildcard masks and implicit deny. Then practise related SAP-C02 ACL questions on filtering logic and placement.
Continuous Improvement for Existing Solutions — This question tests Continuous Improvement for Existing Solutions — Standard ACLs match source addresses..
What is the correct answer to this question?
The correct answer is: The bucket has a bucket policy that denies the pipeline's service role. — Option A is correct. The bucket policy might deny access even if the IAM role allows it, because bucket policies are evaluated in addition to IAM policies. Option B is wrong because the pipeline uses the service role, not Git credentials. Option C is wrong because there is no mention of encryption. Option D is wrong because the error is Access Denied, not a network issue.
What should I do if I get this SAP-C02 question wrong?
Review ACL processing order, placement rules (standard near destination, extended near source), and inbound vs outbound direction. Study wildcard masks and implicit deny. Then practise related SAP-C02 ACL questions on filtering logic and placement.
Are there clue words in this question I should notice?
Yes — watch for: "most likely". Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
What is the key concept behind this question?
Standard ACLs match source addresses.
About these practice questions
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
This SAP-C02 practice question is part of Courseiva's free Amazon Web Services certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the SAP-C02 exam.
Question Discussion
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
Sign in to join the discussion.