The answer is that the bucket policy is missing the aws:SourceVpce condition. When you restrict an S3 bucket policy to a VPC endpoint, you must explicitly include the aws:SourceVpce condition key set to the endpoint ID; without it, S3 evaluates the request as coming from the internet rather than the endpoint, resulting in an AccessDenied error even if the IAM role grants s3:GetObject. On the AWS Certified Security Specialty SCS-C02 exam, this scenario tests your understanding of how VPC endpoint policies interact with bucket policies—a common trap is assuming the IAM role or endpoint policy alone is sufficient, but the bucket policy’s condition is the gatekeeper. Remember the mnemonic “SourceVpce is the key to the VPC endpoint gate”—if it’s missing, access is denied.
SCS-C02 Data Protection Practice Question
This SCS-C02 practice question tests your understanding of data protection. 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 security engineer is troubleshooting an issue where an EC2 instance cannot access an S3 bucket via a VPC endpoint. The bucket policy allows access only from the VPC endpoint. The instance has an IAM role that grants s3:GetObject on the bucket. The EC2 instance receives an AccessDenied error. What is the most likely cause?
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.
The IAM role does not have sufficient permissions.
Why wrong: The role grants s3:GetObject, so permissions should be sufficient from IAM side.
B
The bucket policy does not include the aws:SourceVpce condition.
Without this condition, the bucket policy that restricts to VPC endpoint may not match the request, causing AccessDenied.
C
The VPC endpoint policy is blocking the request.
Why wrong: Endpoint policy could block, but the problem statement says bucket policy allows only from VPC endpoint; the endpoint policy might not be the issue.
D
The EC2 instance's security group does not allow outbound traffic to S3.
Why wrong: Security group would cause a timeout, not an AccessDenied error from S3.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
The bucket policy does not include the aws:SourceVpce condition.
When using a VPC endpoint, the S3 bucket policy must include the condition aws:SourceVpce to allow access from the specific endpoint. If the condition is missing or incorrect, access is denied even if the IAM role allows it. Option C is correct. The IAM role being incorrect would cause a different error; the endpoint policy might override but the bucket policy is the primary issue; the security group might block network access but the error is AccessDenied from S3, not network timeout.
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.
✗
The IAM role does not have sufficient permissions.
Why it's wrong here
The role grants s3:GetObject, so permissions should be sufficient from IAM side.
✓
The bucket policy does not include the aws:SourceVpce condition.
Why this is correct
Without this condition, the bucket policy that restricts to VPC endpoint may not match the request, causing AccessDenied.
Clue confirmation
The clue word "most likely" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
✗
The VPC endpoint policy is blocking the request.
Why it's wrong here
Endpoint policy could block, but the problem statement says bucket policy allows only from VPC endpoint; the endpoint policy might not be the issue.
✗
The EC2 instance's security group does not allow outbound traffic to S3.
Why it's wrong here
Security group would cause a timeout, not an AccessDenied error from S3.
Common exam traps
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.
Detailed technical explanation
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.
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 SCS-C02 exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
Data Protection — This question tests Data Protection — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: The bucket policy does not include the aws:SourceVpce condition. — When using a VPC endpoint, the S3 bucket policy must include the condition aws:SourceVpce to allow access from the specific endpoint. If the condition is missing or incorrect, access is denied even if the IAM role allows it. Option C is correct. The IAM role being incorrect would cause a different error; the endpoint policy might override but the bucket policy is the primary issue; the security group might block network access but the error is AccessDenied from S3, not network timeout.
What should I do if I get this SCS-C02 question wrong?
Identify which SCS-C02 exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
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?
Read the scenario before looking for a memorised answer.
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 SCS-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 SCS-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.