Question 306 of 1,738
Threat Detection and Incident ResponsemediumMultiple ChoiceObjective-mapped

Quick Answer

The answer is that the Kinesis Data Firehose delivery stream lacks an IAM role with permissions to write to the S3 bucket. This is the most likely cause because, while the S3 bucket policy may allow the Firehose service principal to write, Kinesis Data Firehose itself must assume an IAM role that grants explicit PutObject and related permissions on the target bucket. Without that role attached to the delivery stream, the logs cannot be delivered, even if the bucket policy is correctly configured. On the AWS Certified Security Specialty SCS-C02 exam, this scenario tests your understanding of cross-service IAM delegation—a common trap is to assume a bucket policy alone is sufficient, but Firehose always requires its own execution role. Remember the mnemonic: "Firehose needs its own hose"—the delivery stream’s IAM role is the pipe that connects the log flow to S3.

SCS-C02 Threat Detection and Incident Response Practice Question

This SCS-C02 practice question tests your understanding of threat detection and incident response. 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 company has a serverless application using AWS Lambda, API Gateway, and DynamoDB. The security team wants to detect and respond to potential SQL injection attempts in API requests. They have enabled AWS WAF on the API Gateway and created a rule to block SQL injection. However, they also want to capture the blocked requests for analysis and store them in an S3 bucket. The team has configured WAF to send logs to Amazon Kinesis Data Firehose, which delivers to an S3 bucket. After testing, the team notices that the logs are not being delivered. The Firehose delivery stream is in the same AWS account, and the S3 bucket policy allows the Firehose service to write. 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.

Question 1mediummultiple choice
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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

The Kinesis Data Firehose delivery stream does not have an IAM role with permissions to write to the S3 bucket.

Option D is correct because Kinesis Data Firehose requires an IAM role to write to S3, and the role must have the necessary permissions. Even if the bucket policy allows, the delivery stream's IAM role must be configured. Option A is wrong because WAF logs are delivered in near real time, not in batch. Option B is wrong because the bucket policy allows Firehose, but the role is separate. Option C is wrong because WAF is enabled and blocking requests, so it should generate logs.

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 WAF web ACL is not configured to log blocked requests.

    Why it's wrong here

    WAF logging can capture all requests or only blocked ones; if configured, it should work.

  • The Kinesis Data Firehose delivery stream does not have an IAM role with permissions to write to the S3 bucket.

    Why this is correct

    The delivery stream must have an IAM role with s3:PutObject permissions on the bucket.

    Clue confirmation

    The clue word "most likely" in the question point toward this answer.

    Related concept

    Standard ACLs match source addresses.

  • The S3 bucket policy does not grant write permissions to the Firehose delivery stream's IAM role.

    Why it's wrong here

    The bucket policy allows Firehose service principal, but the delivery stream must assume a role with permissions.

  • Kinesis Data Firehose delivers logs in batches every 5 minutes, so the team should wait longer.

    Why it's wrong here

    Firehose delivery can be near real time, but even with batching, logs should appear within minutes.

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 practice questions

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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: The Kinesis Data Firehose delivery stream does not have an IAM role with permissions to write to the S3 bucket. — Option D is correct because Kinesis Data Firehose requires an IAM role to write to S3, and the role must have the necessary permissions. Even if the bucket policy allows, the delivery stream's IAM role must be configured. Option A is wrong because WAF logs are delivered in near real time, not in batch. Option B is wrong because the bucket policy allows Firehose, but the role is separate. Option C is wrong because WAF is enabled and blocking requests, so it should generate logs.

What should I do if I get this SCS-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 SCS-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.

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Last reviewed: Jun 20, 2026

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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.