CAS-004 Security Architecture Practice Question
A company uses an API gateway to manage their microservices. Which security control should the gateway enforce to prevent abuse from excessive API calls?
⚠ Common exam trap
The trap is conflating authentication/authorization with abuse prevention — candidates pick JWT or OAuth because they sound security-related, but only rate limiting addresses request volume.
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
✓
Rate limiting
Rate limiting is the API gateway control that caps the number of requests a client can make within a defined time window (e.g., 100 requests/minute), directly preventing abuse from excessive API calls, brute-force attempts, and denial-of-service. It is enforced at the gateway before requests reach backend microservices.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
JWT verification
Why it's wrong here
JWT verification validates token signature, issuer and expiry, establishing caller identity but not call volume, so it cannot cap excessive requests. It is the right control when the gateway must reject forged or expired tokens before routing to microservices.
- ✗
Input validation
Why it's wrong here
Input validation rejects malformed or malicious payloads, addressing injection and data-shape attacks rather than request frequency. It is correct when the gateway must sanitise parameters before forwarding them, such as blocking SQL injection strings in query fields.
- ✓
Rate limiting
Why this is correct
Rate limiting caps the number of requests a client may make within a defined window, throttling or blocking once the threshold is exceeded. This directly prevents abuse from excessive API calls, the specific threat named in the stem, while preserving availability for legitimate consumers.
- ✗
OAuth 2.0
Why it's wrong here
OAuth 2.0 delegates authorisation and issues access tokens, governing what a client may access, not how many calls it makes. It is the right framework when third-party applications need scoped, delegated access to protected resources.
About these practice questions
Courseiva writes every CAS-005 question from scratch — 973 in total, each with an explanation and a wrong-answer breakdown. None are copied from real exams or dumps. Learn why practice questions differ from exam dumps →
JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official CompTIA exam blueprint
This CAS-005 practice question is part of Courseiva's free CompTIA 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 CAS-005 exam.