SCS-C02 Security Logging and Monitoring Practice Question
A security engineer needs to monitor DNS query logs for malicious domain names. Which THREE services can be used together to collect, analyze, and alert on DNS logs? (Choose THREE.)
⚠ Common exam trap
Watch out — candidates often confuse Amazon GuardDuty's DNS-based threat detection capabilities with the ability to directly collect and alert on custom DNS query logs, but GuardDuty operates on its own internal data sources and does not provide the same level of custom log monitoring and alerting as the combination of Route 53 Resolver Query Logs, CloudWatch Logs, and Lambda.
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
✓
Amazon CloudWatch Logs
Amazon Route 53 Resolver Query Logs (C) is the correct source because it captures DNS queries made by resources in a VPC, including the queried domain name, query type, and response code, which is exactly the raw DNS log data needed for detecting malicious domains. Amazon CloudWatch Logs (A) is correct because Resolver query logs can be published to a CloudWatch Logs log group, where they are stored and made available for metric filters, subscriptions, and retention management. AWS Lambda (B) is correct because a CloudWatch Logs subscription filter can stream matching log events to a Lambda function, which can then parse the DNS records, check domains against threat intelligence, and trigger alerts via SNS or other services. Amazon GuardDuty (D) is not part of this collection/analysis/alerting pipeline for raw DNS query logs; it is a managed threat detection service that analyzes its own findings rather than ingesting and processing Resolver query logs for custom alerting. Amazon Athena (E) is a query service for data in S3 and, while it can analyze logs stored in S3, it is not one of the three services used together here to collect, process, and alert on DNS logs in this scenario.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Amazon CloudWatch Logs
Why this is correct
Amazon CloudWatch Logs acts as the aggregation and monitoring layer for Route 53 Resolver query logs. The resolver service can publish DNS query logs directly to a CloudWatch Logs log group, where you can create metric filters and subscription filters to detect suspicious queries. CloudWatch Logs supports near-real-time querying with Logs Insights, making it a central destination for ongoing monitoring.
- ✓
AWS Lambda
Why this is correct
AWS Lambda can be triggered by CloudWatch Logs subscription filters to asynchronously process each DNS query log event as it arrives. A Lambda function can parse domain names, compare them against threat intelligence feeds, and publish findings to SNS or Security Hub. This serverless pattern enables custom alerting logic that is difficult to implement with CloudWatch alarms alone, making Lambda a correct component for monitoring DNS query logs.
- ✓
Amazon Route 53 Resolver Query Logs
Why this is correct
Amazon Route 53 Resolver Query Logs are the actual source of the DNS query data in a VPC, capturing every query made by EC2 instances, Lambda functions, and other resources. When enabled, this feature sends the logs to a destination such as CloudWatch Logs, S3, or Kinesis Data Firehose. Without enabling Route 53 Resolver Query Logs, the monitoring pipeline would have no DNS logs to analyze.
- ✗
Amazon GuardDuty
Why it's wrong here
Amazon GuardDuty does perform its own threat detection using DNS request data from AWS internal telemetry, but it cannot accept or ingest user-managed Route 53 Resolver query logs. The service's DNS monitoring is built-in and separate from the custom logging pipeline the security engineer is trying to build. Therefore, GuardDuty is not a destination or processing option for the specific DNS query logs collected for this monitoring requirement.
- ✗
Amazon Athena
Why it's wrong here
Amazon Athena is an interactive query service that only reads data directly from Amazon S3, not from CloudWatch Logs. While you could export Route 53 Resolver query logs to S3 and query them with Athena for historical analysis, the question focuses on ongoing monitoring of the logs, which requires immediate filtering and alerting. Since Athena lacks push-based scanning of streaming log groups, it does not fit as the primary monitoring tool for this scenario.
Visual reference
Quick reference
AWS S3 Storage Class Comparison
| Storage Class | Min Duration | Retrieval | Use Case |
|---|---|---|---|
| S3 Standard | None | Immediate | Frequently accessed data |
| S3 Standard-IA | 30 days | Immediate | Infrequent access, rapid retrieval |
| S3 One Zone-IA | 30 days | Immediate | Non-critical infrequent data |
| S3 Intelligent-Tiering | None | Immediate–hours | Unknown or changing access patterns |
| S3 Glacier Instant | 90 days | Milliseconds | Archive with instant retrieval |
| S3 Glacier Flexible | 90 days | Minutes–hours | Archive, flexible retrieval |
| S3 Glacier Deep Archive | 180 days | Hours | Long-term compliance archive |
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
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.