Quick Answer
The answer is AWS Shield Advanced, the correct choice because it provides dedicated, always-on network-layer DDoS mitigation that absorbs and scrubs malicious traffic before it ever reaches your Application Load Balancer. Unlike AWS WAF, which operates at the application layer (Layer 7) inspecting HTTP requests, Shield Advanced uses flow-based detection and inline mitigation at Layers 3 and 4, making it purpose-built for defending against volumetric attacks like UDP floods or SYN floods targeting the ALB’s IP address. On the AWS Certified Security Specialty SCS-C02 exam, this question tests your ability to distinguish between layered defense services: a common trap is confusing WAF (Layer 7) with Shield Advanced (Layer 3/4), or assuming stateless NACLs can handle DDoS. Remember the memory tip: “Shield stops the flood, WAF stops the fraud”—Shield Advanced blocks the network-layer deluge, while WAF filters application-layer exploits.
This SCS-C02 practice question tests your understanding of infrastructure security. 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 company runs a critical application on EC2 instances behind an Application Load Balancer. The security team suspects that a DDoS attack is targeting the application. Which AWS service can be used to absorb and mitigate the attack at the network layer before traffic reaches the ALB?
AWS WAF
Why wrong: WAF protects at the application layer, not network layer DDoS.
AWS Identity and Access Management (IAM)
Why wrong: IAM manages access, not DDoS mitigation.
Network ACLs
Why wrong: NACLs are stateless and not effective against DDoS.
AWS Shield Advanced
Shield Advanced provides network and transport layer DDoS protection.
Answer choices
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
AWS Shield Advanced
Option C is correct because AWS Shield Advanced provides enhanced DDoS mitigation for ALB. Option A is wrong because IAM is for access management. Option B is wrong because WAF is for application layer. Option D is wrong because NACLs are stateless and not designed for DDoS mitigation.
Key principle: ACLs process entries top to bottom and stop at the first match. Entry order and interface direction matter as much as the permit or deny statement.
Answer analysis
For each option: why learners choose it and why it is or isn't the right answer here.
AWS WAF
Why it's wrong here
WAF protects at the application layer, not network layer DDoS.
AWS Identity and Access Management (IAM)
Why it's wrong here
IAM manages access, not DDoS mitigation.
Network ACLs
Why it's wrong here
NACLs are stateless and not effective against DDoS.
AWS Shield Advanced
Why this is correct
Shield Advanced provides network and transport layer DDoS protection.
Related concept
Standard ACLs match source addresses.
Common exam traps
ACLs are processed top to bottom. The first matching entry wins, and an implicit deny usually exists at the end.
Detailed technical explanation
ACL questions test precision: source, destination, protocol, port and direction. A generally correct ACL can still fail if it is applied on the wrong interface or in the wrong direction.
Key takeaway
ACLs process entries top to bottom and stop at the first match. Entry order and interface direction matter as much as the permit or deny statement.
Real-world example
A company's IT admin needs to give a contractor read-only access to production logs without sharing account credentials. Using role-based access control (RBAC) and temporary scoped permissions — not a permanent shared password — is the correct pattern. Questions like this test whether you can apply least-privilege access across cloud identity services.
What to study next
Review ACL processing order, placement rules (standard near destination, extended near source), and inbound vs outbound direction. Study wildcard masks and implicit deny. Then practise related SCS-C02 ACL questions on filtering logic and placement.
Infrastructure Security — study guide chapter
Learn the concepts, then practise the questions
Infrastructure Security 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
Infrastructure Security — This question tests Infrastructure Security — Standard ACLs match source addresses..
The correct answer is: AWS Shield Advanced — Option C is correct because AWS Shield Advanced provides enhanced DDoS mitigation for ALB. Option A is wrong because IAM is for access management. Option B is wrong because WAF is for application layer. Option D is wrong because NACLs are stateless and not designed for DDoS mitigation.
Review ACL processing order, placement rules (standard near destination, extended near source), and inbound vs outbound direction. Study wildcard masks and implicit deny. Then practise related SCS-C02 ACL questions on filtering logic and placement.
Standard ACLs match source addresses.
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 →
Last reviewed: Jun 20, 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.