SCS-C02 Threat Detection and Incident Response Practice Question
A company wants to use AWS services to detect and respond to a potential DDoS attack on their web application hosted on EC2 instances behind an Application Load Balancer (ALB). Which TWO AWS services should the company use for detection and mitigation?
⚠ Common exam trap
Test-takers frequently confuse AWS Shield Advanced (which provides network-layer DDoS detection and mitigation) with AWS WAF (which provides application-layer filtering), but the question requires both detection and mitigation, and Shield Advanced alone does not offer the granular application-layer rule customization that WAF provides for an ALB-based web application.
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
✓
AWS WAF
AWS WAF is correct because it allows you to create web access control lists (web ACLs) to filter and monitor HTTP/HTTPS requests to your Application Load Balancer. By defining rate-based rules, you can automatically block IP addresses that exceed a threshold of requests per 5-minute window, mitigating layer 7 DDoS attacks such as HTTP floods or SQL injection attempts.
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 WAF
Why this is correct
AWS WAF is a web application firewall that can detect and respond to application-layer DDoS attacks by creating rate-based rules that automatically block or rate-limit requests from a single IP address once a configured threshold is exceeded. It also supports custom rules for HTTP inspection, making it a direct, policy-driven tool for DDoS mitigation. WAF integrates with CloudFront, Application Load Balancer, and API Gateway to enforce these rules in real time at the edge or ingestion point.
- ✓
AWS Shield Advanced
Why this is correct
AWS Shield Advanced is a dedicated DDoS protection service that provides always-on detection and automatic inline mitigation for volumetric, state-exhaustion, and application-layer attacks targeting resources such as EC2, CloudFront, and Route 53. It offers enhanced visibility through CloudWatch metrics, integrates with AWS WAF for application-layer controls, and gives access to the DDoS Response Team for proactive support. Unlike WAF alone, it addresses large infrastructure-level threats and includes cost protection against scaling during attacks.
- ✗
Amazon Route 53
Why it's wrong here
Amazon Route 53 is a highly available DNS service, not a DDoS detection or response tool. Although its global anycast network and DNS query resolution inherently provide some resilience to DNS reflection attacks, Route 53 does not offer configurable rate rules, live traffic inspection, or automated mitigation policies specific to DDoS. Using Route 53 alone cannot detect an ongoing attack or take automated blocking actions.
- ✗
Amazon CloudFront
Why it's wrong here
Amazon CloudFront is a content delivery network that can help absorb DDoS traffic by distributing requests across its global edge locations, but it is fundamentally a CDN, not a detection service. It does not natively provide DDoS alerts, per-IP rate limiting, or automated attack response out of the box. Instead, it serves as an architectural layer in a DDoS-resilient design, working alongside Shield Advanced and WAF to drop malicious traffic before it reaches the origin.
- ✗
Amazon GuardDuty
Why it's wrong here
Amazon GuardDuty is a machine-learning-based threat detection service that analyzes AWS API logs, DNS queries, and network traffic to identify security issues like brute-force attempts, compromised EC2 instances, or crypto mining. It does not specifically detect DDoS attacks because a DDoS is an overwhelming flood of incoming traffic rather than a malicious activity pattern within your infrastructure. GuardDuty might flag related symptoms, such as unexpected outbound traffic from a targeted instance, but it lacks real-time packet inspection and rate-based enforcement needed for DDoS response.
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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.