Question 327 of 1,738
Threat Detection and Incident ResponsehardMultiple ChoiceObjective-mapped

Quick Answer

The correct answer is to use Amazon GuardDuty to send findings to Amazon EventBridge, which triggers an AWS Lambda function that modifies the security group to remove the instance. This works because GuardDuty detects threats like communication with known malicious IPs and publishes findings as events; EventBridge then routes those events to Lambda, which programmatically revokes the security group rules associated with the EC2 instance, cutting off all network traffic and effectively isolating it. On the AWS Certified Security Specialty SCS-C02 exam, this scenario tests your understanding of automated incident response workflows—specifically how to chain GuardDuty, EventBridge, and Lambda for EC2 isolation. A common trap is choosing a solution that terminates or stops the instance instead of isolating it via security groups, which is often not the requirement. Remember the memory tip: “Guard finds, Bridge binds, Lambda unbinds.”

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 security requirement to automatically isolate an Amazon EC2 instance that is generating high network traffic to a known malicious IP address. The company uses Amazon GuardDuty and AWS Lambda. Which combination of services and configurations should be used to achieve the isolation?

Question 1hardmultiple 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

Use Amazon GuardDuty to send findings to Amazon CloudWatch Events, which triggers an AWS Lambda function that modifies the security group to remove the instance.

Option C is correct because Amazon GuardDuty generates findings for threats like communication with known malicious IPs, and these findings can be sent to Amazon CloudWatch Events (now Amazon EventBridge). CloudWatch Events can then trigger an AWS Lambda function that modifies the security group associated with the EC2 instance to remove its inbound/outbound rules, effectively isolating the instance. This automated workflow meets the security requirement without manual intervention.

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 VPC Flow Logs to send logs to CloudWatch Logs, then create a metric filter that triggers a Lambda function.

    Why it's wrong here

    This approach is more complex and less direct.

  • Use Amazon GuardDuty to send findings to AWS Systems Manager Automation to run a document that isolates the instance.

    Why it's wrong here

    Systems Manager Automation can be used but requires additional setup; Lambda is simpler.

  • Use Amazon GuardDuty to send findings to Amazon CloudWatch Events, which triggers an AWS Lambda function that modifies the security group to remove the instance.

    Why this is correct

    This is a standard pattern for automated response.

    Related concept

    Read the scenario before looking for a memorised answer.

  • Use AWS Config rules to detect the traffic and invoke a Lambda function to change the security group.

    Why it's wrong here

    AWS Config does not monitor traffic patterns.

Common exam traps

Common exam trap: answer the scenario, not the keyword

The trap here is that candidates may think GuardDuty can directly trigger Systems Manager Automation (Option B) without the intermediate CloudWatch Events step, or they may confuse AWS Config's compliance evaluation with real-time network threat detection (Option D).

Detailed technical explanation

How to think about this question

GuardDuty findings are structured as JSON events that include details like the EC2 instance ID, the malicious IP, and the threat type (e.g., UnusualTraffic). CloudWatch Events (EventBridge) uses event patterns to match specific GuardDuty finding types, such as 'UnauthorizedAccess:EC2/MaliciousIPCaller.Custom', and routes them to a Lambda function. The Lambda function can use the AWS SDK to describe the instance's security groups, revoke all inbound and outbound rules, and optionally add a deny-all rule, effectively isolating the instance within seconds of the finding.

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 company's IT admin needs to give a contractor read-only access to production logs without sharing account credentials. Using role-based access control (RBAC) and temporary scoped permissions — not a permanent shared password — is the correct pattern. Questions like this test whether you can apply least-privilege access across cloud identity services.

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.

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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 — Read the scenario before looking for a memorised answer..

What is the correct answer to this question?

The correct answer is: Use Amazon GuardDuty to send findings to Amazon CloudWatch Events, which triggers an AWS Lambda function that modifies the security group to remove the instance. — Option C is correct because Amazon GuardDuty generates findings for threats like communication with known malicious IPs, and these findings can be sent to Amazon CloudWatch Events (now Amazon EventBridge). CloudWatch Events can then trigger an AWS Lambda function that modifies the security group associated with the EC2 instance to remove its inbound/outbound rules, effectively isolating the instance. This automated workflow meets the security requirement without manual intervention.

What should I do if I get this SCS-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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Last reviewed: Jun 24, 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.