hardMultiple ChoiceObjective-mapped
CAS-004 Practice Question: A security architect at a financial institution…
A security architect at a financial institution is designing a cloud-native application using AWS. The application processes sensitive customer data and must comply with PCI DSS. Which of the following security architecture decisions best supports both compliance and operational efficiency?
⚠ Common exam trap
The CAS-004 exam often tests the misconception that network isolation (Option A) or a single security tool (Option B) is sufficient for compliance, when in reality PCI DSS requires a layered approach including encryption key management and data access governance, which a CASB and CMKs directly address.
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
✓
Implement a cloud access security broker (CASB) and use customer-managed encryption keys (CMKs) for data at rest
A CASB provides visibility and control over data in cloud environments, which is critical for PCI DSS compliance, while customer-managed encryption keys (CMKs) give the institution direct control over encryption of data at rest, meeting both compliance requirements and operational flexibility. This combination allows the financial institution to enforce data protection policies and audit access without sacrificing the agility of cloud-native deployment.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Place all application resources in a VPC with no internet gateway and use VPC endpoints for AWS services
Why it's wrong here
This limits exposure but does not fulfill PCI DSS encryption and access control requirements.
- ✗
Use a cloud-based web application firewall (WAF) and enable logging for all API calls
Why it's wrong here
A WAF protects against web attacks but does not cover data-at-rest encryption or key management.
- ✗
Deploy the application on a single tenant dedicated instance and rely on the cloud provider's compliance certifications
Why it's wrong here
This does not address specific PCI DSS controls like encryption and access management.
- ✓
Implement a cloud access security broker (CASB) and use customer-managed encryption keys (CMKs) for data at rest
Why this is correct
CASB provides visibility and policy enforcement; CMKs meet PCI DSS encryption requirements.
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
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.