CAS-004 Security Architecture Practice Question
An organization wants to implement infrastructure as code (IaC) with immutable infrastructure. Which security benefit does immutable infrastructure provide?
⚠ Common exam trap
CAS-005 often tests whether candidates confuse immutable infrastructure's security benefit (consistent, drift-free configurations reducing attack surface) with operational benefits like easier patching or performance gains.
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
✓
Reduced attack surface due to consistent configurations
Immutable infrastructure means servers and components are never modified after deployment — instead, changes require replacing the entire instance with a newly built, tested image. This eliminates configuration drift, ensures every instance matches a known-good baseline, and removes the accumulated patches, leftover packages, and ad-hoc changes that attackers exploit, thereby reducing the attack surface. The other options describe operational or performance benefits, not the core security advantage.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Better performance through caching
Why it's wrong here
Caching is a performance mechanism, not a security property; immutable infrastructure replaces rather than patches instances, so no persistent cache layer provides the stated benefit. It is tempting because caching does improve throughput in some deployment patterns, and would be the answer if the question asked how to reduce latency rather than which security benefit immutability delivers.
- ✓
Reduced attack surface due to consistent configurations
Why this is correct
Immutable infrastructure replaces rather than patches instances, so every deployment derives from one hardened image. Drift and configuration creep disappear, and no lingering services or stale packages accumulate, which is precisely the consistent-configuration reduction of attack surface the stem asks for.
- ✗
Simpler network segmentation
Why it's wrong here
Segmentation is achieved through network controls such as security groups, subnets and firewalls, not through instance immutability; rebuilding servers does not itself partition traffic. It is tempting because IaC can codify network rules, so this would be correct if the question asked how to define segmentation declaratively rather than what security benefit immutable infrastructure provides.
- ✗
Easier patch management
Why it's wrong here
Immutable infrastructure replaces instances rather than patching them in place, so routine patch management largely disappears — but that is an operational consequence, not the security benefit the question asks for. It tempts because patch automation is genuinely valuable where long-lived servers persist; here, replacement from a known-good image is the point.
About these practice questions
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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.