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 security engineer is setting up automated incident response for a compromised EC2 instance. The engineer wants to isolate the instance immediately upon detection of a GuardDuty finding. Which AWS service can be used to automatically trigger a Lambda function that modifies the instance's security group?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue: "immediately / without restart"
Why it matters: Time or reboot constraint — the correct answer must take effect right away without requiring a reboot or reload.
AWS Step Functions
Why wrong: Step Functions can be used but requires a trigger; CloudWatch Events is the primary integration.
Amazon Inspector
Why wrong: Inspector does not trigger automated responses to GuardDuty findings.
Amazon CloudWatch Events
CloudWatch Events can match GuardDuty findings and invoke Lambda functions.
AWS Config
Why wrong: AWS Config does not directly trigger Lambda based on GuardDuty findings.
Answer choices
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
Amazon CloudWatch Events
Amazon CloudWatch Events (now part of Amazon EventBridge) can be configured with a rule that matches specific GuardDuty finding events. When a finding is detected, the rule triggers a Lambda function that can modify the EC2 instance's security group to isolate it, for example by removing all inbound rules or replacing the group with a restrictive one. This provides the automated, event-driven response required.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
For each option: why learners choose it and why it is or isn't the right answer here.
AWS Step Functions
Why it's wrong here
Step Functions can be used but requires a trigger; CloudWatch Events is the primary integration.
Amazon Inspector
Why it's wrong here
Inspector does not trigger automated responses to GuardDuty findings.
Amazon CloudWatch Events
Why this is correct
CloudWatch Events can match GuardDuty findings and invoke Lambda functions.
Clue confirmation
The clue word "immediately / without restart" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
AWS Config
Why it's wrong here
AWS Config does not directly trigger Lambda based on GuardDuty findings.
Common exam traps
The trap here is that candidates may confuse Amazon Inspector (a vulnerability scanner) with GuardDuty (a threat detection service), or assume AWS Config's compliance rules can react to security findings, when in fact only CloudWatch Events/EventBridge provides the direct event-driven trigger for GuardDuty findings.
Detailed technical explanation
Under the hood, GuardDuty publishes findings as events to the default event bus in Amazon EventBridge (formerly CloudWatch Events). A rule with an event pattern matching the 'GuardDuty Finding' source can invoke a Lambda function, passing the finding details as a JSON payload. The Lambda function can then use the EC2 API (e.g., ModifySecurityGroupRules or RevokeSecurityGroupIngress) to remove all inbound rules, effectively isolating the instance. A real-world scenario might involve using a dedicated 'quarantine' security group that denies all traffic, which the Lambda function applies by replacing the instance's current security group association.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
A healthcare organisation deploys an application with a public-facing web tier and a private database tier. The database subnet has no public IP and only accepts connections from the web tier's security group. Questions like this test whether you can design cloud network isolation using VNets/VPCs, subnets, and security group rules.
What to study next
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Threat Detection and Incident Response — study guide chapter
Learn the concepts, then practise the questions
Threat Detection and Incident Response practice questions
Targeted practice on this topic area only
All SCS-C02 questions
1,738 questions across all exam domains
AWS Certified Security Specialty SCS-C02 study guide
Full concept coverage aligned to exam objectives
SCS-C02 practice test guide
How to use practice tests most effectively before exam day
Related practice questions
Use these pages to review the topic behind this question. This is how one missed question becomes focused revision.
Practise SCS-C02 questions linked to Threat Detection and Incident Response.
Practise SCS-C02 questions linked to Security Logging and Monitoring.
Practise SCS-C02 questions linked to Identity and Access Management.
Practise SCS-C02 questions linked to Management and Security Governance.
Practise SCS-C02 questions linked to Infrastructure Security.
Practise SCS-C02 questions linked to Data Protection.
Practise SCS-C02 questions linked to SCS-C02 fundamentals.
Practise SCS-C02 questions linked to SCS-C02 scenario.
Practise SCS-C02 questions linked to SCS-C02 troubleshooting.
Practice this exam
Short sessions build daily habit. Longer sessions build exam-day stamina. Try a timed session to simulate real conditions.
FAQ
Threat Detection and Incident Response — This question tests Threat Detection and Incident Response — Read the scenario before looking for a memorised answer..
The correct answer is: Amazon CloudWatch Events — Amazon CloudWatch Events (now part of Amazon EventBridge) can be configured with a rule that matches specific GuardDuty finding events. When a finding is detected, the rule triggers a Lambda function that can modify the EC2 instance's security group to isolate it, for example by removing all inbound rules or replacing the group with a restrictive one. This provides the automated, event-driven response required.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Yes — watch for: "immediately / without restart". Time or reboot constraint — the correct answer must take effect right away without requiring a reboot or reload.
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 →
Keep practising
Last reviewed: Jun 24, 2026
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.