Amazon GuardDuty is the correct choice because it is the AWS managed threat detection service specifically designed to analyze VPC Flow Logs, AWS CloudTrail event logs, and DNS logs for identifying malicious activity and unauthorized behavior. This service continuously monitors these data sources using machine learning, anomaly detection, and integrated threat intelligence to detect threats like credential compromise, cryptocurrency mining, and API abuse without requiring additional security software. On the AWS Certified Cloud Practitioner CLF-C02 exam, this question tests your understanding of core AWS security services and their specific monitoring capabilities; a common trap is confusing GuardDuty with services like AWS Security Hub or Amazon Inspector, but remember that GuardDuty is the only one focused on threat detection from network and account activity logs. For a quick memory tip, think of GuardDuty as the “guard” that “dutifully” watches your flow logs, CloudTrail, and DNS—three data sources that spell “VCD” (VPC, CloudTrail, DNS).
CLF-C02 Security and Compliance Practice Question
This CLF-C02 practice question tests your understanding of security and compliance. 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.
Which AWS service provides managed threat detection that analyzes VPC Flow Logs, AWS CloudTrail events, and DNS logs to identify malicious activity and unauthorized behavior?
Why wrong: Security Hub aggregates and prioritizes findings from GuardDuty and other services — it doesn't perform the underlying threat detection.
B
Amazon Inspector
Why wrong: Inspector scans for vulnerabilities in EC2 and container images — it doesn't analyze log data for behavioral threats.
C
Amazon GuardDuty
GuardDuty uses ML and threat intelligence to analyze VPC Flow Logs, CloudTrail, and DNS logs for active threats like compromised instances and account takeovers.
D
AWS Config
Why wrong: Config evaluates resource configurations against compliance rules — it doesn't analyze network and API behavior for security threats.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Amazon GuardDuty
Amazon GuardDuty is a managed threat detection service that continuously monitors for malicious activity and unauthorized behavior by analyzing VPC Flow Logs, AWS CloudTrail event logs, and DNS logs. It uses machine learning, anomaly detection, and integrated threat intelligence to identify threats such as credential compromise, cryptocurrency mining, and API abuse without requiring additional security software or infrastructure.
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.
✗
AWS Security Hub
Why it's wrong here
Security Hub aggregates and prioritizes findings from GuardDuty and other services — it doesn't perform the underlying threat detection.
✗
Amazon Inspector
Why it's wrong here
Inspector scans for vulnerabilities in EC2 and container images — it doesn't analyze log data for behavioral threats.
✓
Amazon GuardDuty
Why this is correct
GuardDuty uses ML and threat intelligence to analyze VPC Flow Logs, CloudTrail, and DNS logs for active threats like compromised instances and account takeovers.
Related concept
Read the scenario before looking for a memorised answer.
✗
AWS Config
Why it's wrong here
Config evaluates resource configurations against compliance rules — it doesn't analyze network and API behavior for security threats.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates confuse AWS Security Hub (a central dashboard for findings) with GuardDuty (the actual threat detection engine), or assume Amazon Inspector performs network traffic analysis when it only scans for software vulnerabilities and network reachability.
Detailed technical explanation
How to think about this question
GuardDuty operates by ingesting and processing VPC Flow Logs (including metadata like source/destination IP, port, and protocol), CloudTrail management and data events, and DNS query logs from Route 53 Resolver. It uses a combination of rule-based detection (e.g., known malicious IP feeds from AWS and third-party sources) and machine learning models that establish baselines of normal account behavior to flag anomalies such as unusual data transfer patterns or API calls from unexpected geographies. In a real-world scenario, GuardDuty can detect a compromised IAM key by correlating an API call from an unusual location with a subsequent brute-force attempt on an EC2 instance, all without requiring agent installation.
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 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.
Related glossary terms
Concepts from this question explained
These glossary pages explain the core terms tested in this CLF-C02 question in full detail.
Security and Compliance — This question tests Security and Compliance — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Amazon GuardDuty — Amazon GuardDuty is a managed threat detection service that continuously monitors for malicious activity and unauthorized behavior by analyzing VPC Flow Logs, AWS CloudTrail event logs, and DNS logs. It uses machine learning, anomaly detection, and integrated threat intelligence to identify threats such as credential compromise, cryptocurrency mining, and API abuse without requiring additional security software or infrastructure.
What should I do if I get this CLF-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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Question Discussion
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