SCS-C02 Threat Detection and Incident Response Practice Question
This SCS-C02 practice question tests your understanding of threat detection and incident response. Match the stated requirement to the specific cloud service, access model, or configuration option — many options are valid in isolation but not for this scenario. 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 startup uses a single AWS account for development. The security engineer wants to detect if any EC2 instances have been compromised and are performing reconnaissance by probing open ports on other internal instances. The engineer has enabled VPC Flow Logs for all subnets. What is the most cost-effective way to detect this behavior?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Enable Amazon GuardDuty and review the findings.
Amazon GuardDuty is a managed threat detection service that uses machine learning and integrated threat intelligence to analyze VPC Flow Logs, DNS logs, and other data sources. It can automatically detect reconnaissance behavior such as port probing or port scanning from compromised EC2 instances without requiring any additional infrastructure or manual query setup. This makes it the most cost-effective solution because it operates on a pay-per-volume basis and eliminates the need for custom log analysis or per-instance agents.
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.
Read the scenario before looking for a memorised answer.
✗
Install a third-party intrusion detection system on each EC2 instance.
Why it's wrong here
Costly and complex.
✗
Use Amazon CloudWatch Logs Insights to query VPC Flow Logs for rejected traffic patterns.
Why it's wrong here
Manual and not as effective as GuardDuty.
✗
Use AWS Config rules to check for security group changes.
Why it's wrong here
Does not detect scanning behavior.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often assume querying VPC Flow Logs directly with CloudWatch Logs Insights is the most cost-effective approach, but they overlook the operational cost and lack of automation, while GuardDuty provides automated, managed detection with no manual query overhead.
Detailed technical explanation
How to think about this question
GuardDuty analyzes VPC Flow Logs for patterns like sequential port connection attempts from a single source to multiple destinations, which is indicative of port scanning. It also correlates this with threat intelligence feeds to identify known malicious IPs or behaviors. Under the hood, GuardDuty uses a combination of anomaly detection and signature-based detection, and it can generate findings for specific reconnaissance techniques such as 'Recon:EC2/PortProbeUnprotectedPort' or 'Recon:EC2/Portscan'.
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 startup's cloud architect reviews their monthly bill and notices costs are higher than expected for a long-running batch job. Switching from on-demand instances to Reserved Instances — or using Spot/Preemptible VMs — can reduce compute costs by up to 72 %. Questions like this test whether you understand the tradeoffs between commitment, flexibility, and cost across cloud pricing models.
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.
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: Enable Amazon GuardDuty and review the findings. — Amazon GuardDuty is a managed threat detection service that uses machine learning and integrated threat intelligence to analyze VPC Flow Logs, DNS logs, and other data sources. It can automatically detect reconnaissance behavior such as port probing or port scanning from compromised EC2 instances without requiring any additional infrastructure or manual query setup. This makes it the most cost-effective solution because it operates on a pay-per-volume basis and eliminates the need for custom log analysis or per-instance agents.
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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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
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