← SCS-C02·Amazon Web Services

Question 35 of 1,738

Threat Detection and Incident Response →hardMultiple ChoiceObjective-mapped

Quick Answer

The correct answer is to check the S3 bucket policy for any explicit deny statements that might block the Lambda function's role. Even when an IAM role grants full permissions to modify bucket policies, an explicit deny in the target bucket’s resource-based policy overrides any allow—this is a core principle of AWS authorization logic. On the AWS Certified Security Specialty SCS-C02 exam, this scenario tests your understanding of how resource-based policies interact with identity-based policies, often appearing as a trap where candidates assume the Lambda role’s permissions are sufficient. A common mistake is to overlook the bucket policy itself when the function is in the same account, but explicit denies are absolute. Remember the memory tip: “Deny always wins”—if a bucket policy says no, no IAM policy can say yes.

SCS-C02 Threat Detection and Incident Response Practice Question

This SCS-C02 practice question tests your understanding of threat detection and incident response. 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 Amazon GuardDuty and AWS Security Hub. The security team has configured a custom insight in Security Hub to track findings related to S3 bucket exposures. They want to automatically remediate these findings by applying an S3 bucket policy that blocks public access. The team has created a Lambda function that applies the bucket policy and configured Security Hub to send findings to the Lambda function via a custom action. However, when a new finding is generated, the Lambda function is invoked but fails to apply the policy because it does not have permission to modify the S3 bucket. The Lambda function's execution role has permissions to modify S3 bucket policies, but the function is in the same account as the bucket. What should the team check?

Question 1hardmultiple choice

Full question →

A
Add the Lambda function's execution role to the bucket's Access Control List (ACL).
Why wrong: ACLs are legacy and not recommended for permissions management.
B
Ensure that the Lambda function's execution role has a trust policy that allows Security Hub to assume it.
Why wrong: Security Hub does not assume the Lambda role; it invokes the function.
C
Check the S3 bucket policy for any explicit deny statements that might block the Lambda function's role.
An explicit deny in the bucket policy would prevent the role from modifying it.
D
Verify that the S3 bucket's block public access settings are not preventing the policy update.
Why wrong: Block public access settings can be overridden by bucket policies, but the function may still be able to update the policy.

Full breakdown with real-world context →

Answer choices

Why each option matters

Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.

Correct answer & explanation

✓

Check the S3 bucket policy for any explicit deny statements that might block the Lambda function's role.

Option C is correct because even if the function has permissions, the bucket policy may explicitly deny access to the Lambda function's role. Option A is wrong because the function is in the same account, so cross-account is not needed. Option B is wrong because S3 block public access settings are separate from bucket policies. Option D is wrong because the function has permissions; the issue is likely at the bucket policy level.

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.

✗
Add the Lambda function's execution role to the bucket's Access Control List (ACL).
Why it's wrong here
ACLs are legacy and not recommended for permissions management.
✗
Ensure that the Lambda function's execution role has a trust policy that allows Security Hub to assume it.
Why it's wrong here
Security Hub does not assume the Lambda role; it invokes the function.
✓
Check the S3 bucket policy for any explicit deny statements that might block the Lambda function's role.
Why this is correct
An explicit deny in the bucket policy would prevent the role from modifying it.
Related concept
Standard ACLs match source addresses.
✗
Verify that the S3 bucket's block public access settings are not preventing the policy update.
Why it's wrong here
Block public access settings can be overridden by bucket policies, but the function may still be able to update the policy.

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 SCS-C02 ACL questions on filtering logic and placement.

Related SCS-C02 practice-question pages

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

Threat Detection and Incident Response practice questions

Practise SCS-C02 questions linked to Threat Detection and Incident Response.

Security Logging and Monitoring practice questions

Practise SCS-C02 questions linked to Security Logging and Monitoring.

Identity and Access Management practice questions

Practise SCS-C02 questions linked to Identity and Access Management.

Management and Security Governance practice questions

Practise SCS-C02 questions linked to Management and Security Governance.

Infrastructure Security practice questions

Practise SCS-C02 questions linked to Infrastructure Security.

Data Protection practice questions

Practise SCS-C02 questions linked to Data Protection.

SCS-C02 fundamentals practice questions

Practise SCS-C02 questions linked to SCS-C02 fundamentals.

SCS-C02 scenario practice questions

Practise SCS-C02 questions linked to SCS-C02 scenario.

SCS-C02 troubleshooting practice questions

Practise SCS-C02 questions linked to SCS-C02 troubleshooting.

Practice this exam

Start a free SCS-C02 practice session

Short sessions build daily habit. Longer sessions build exam-day stamina. Try a timed session to simulate real conditions.

10 questions 20 questions 30 questions 50 questions Timed 30

SCS-C02 practice-test guide →Study guide →Browse all practice tests

FAQ

Questions learners often ask

What does this SCS-C02 question test?

Threat Detection and Incident Response — This question tests Threat Detection and Incident Response — Standard ACLs match source addresses..

What is the correct answer to this question?

The correct answer is: Check the S3 bucket policy for any explicit deny statements that might block the Lambda function's role. — Option C is correct because even if the function has permissions, the bucket policy may explicitly deny access to the Lambda function's role. Option A is wrong because the function is in the same account, so cross-account is not needed. Option B is wrong because S3 block public access settings are separate from bucket policies. Option D is wrong because the function has permissions; the issue is likely at the bucket policy level.

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

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 →

How Courseiva writes practice questions · Editorial policy

Keep practising

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.

Loading comments…

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.