CAS-004 Security Engineering Practice Question
A security engineer is implementing a secure software development lifecycle (SDLC) for a new application. The engineer needs to integrate security activities that help identify and mitigate vulnerabilities early in the development process. Which of the following activities should be included? (Choose two.)
⚠ Common exam trap
The trap here is selecting activities that are security-related but occur too late (like penetration testing) or are not directly vulnerability-identifying (like training).
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
✓
Static application security testing (SAST) in the CI/CD pipeline.
Threat modeling during design and SAST in the CI/CD pipeline are both early-stage activities that help identify and mitigate vulnerabilities before deployment. Threat modeling addresses design flaws, while SAST catches coding errors. Together, they shift security left and reduce remediation costs.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Static application security testing (SAST) in the CI/CD pipeline.
Why this is correct
SAST analyzes source code for vulnerabilities without executing it, enabling early detection of issues like SQL injection or buffer overflows. Integrating SAST into the CI/CD pipeline ensures continuous security checks. This helps developers fix flaws before deployment, reducing risk.
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Security awareness training for developers.
Why it's wrong here
Security awareness training is important for building a security culture, but it is not a direct technical activity that identifies vulnerabilities in the application. It supports secure coding practices but does not itself find or mitigate flaws in the codebase.
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Penetration testing after production deployment.
Why it's wrong here
Penetration testing after production deployment is a late-stage activity and does not help identify vulnerabilities early in development. While valuable, it is not part of shifting security left. It should be complemented by earlier activities like threat modeling and SAST.
- ✓
Threat modeling during the design phase.
Why this is correct
Threat modeling during design helps identify potential security threats and design flaws before code is written. It allows the team to address risks proactively, reducing the cost of fixes later. This is a core activity in a secure SDLC, aligning with shifting security left.
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Dynamic application security testing (DAST) during the design phase.
Why it's wrong here
DAST requires a running application, so it cannot be performed during the design phase. It is typically used in testing or staging environments. Therefore, it is not suitable for early design-phase security activities, though it can be part of later testing.
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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.