CAS-004 Security Architecture Practice Question
A container security team wants to enforce that containers run with the least privileges possible. Which Linux security module can be used to restrict system calls available to a container?
⚠ Common exam trap
CAS-005 often tests the distinction between Linux Security Modules (AppArmor, SELinux) and seccomp — candidates pick AppArmor or SELinux for syscall restriction, but only seccomp filters system calls; LSMs enforce resource access control.
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
✓
seccomp
seccomp (secure computing mode) is a Linux kernel feature that filters system calls, allowing a container to be restricted to only the syscalls it needs. In container runtimes like Docker, containerd, and Kubernetes, seccomp profiles are applied per container to enforce least privilege at the syscall level. This directly answers 'restrict system calls available to a container.'
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Pod Security Policy
Why it's wrong here
Pod Security Policy governs pod admission in Kubernetes, not Linux system calls. It is tempting because it does restrict container privileges, but it was deprecated in Kubernetes 1.21 and never operated as a Linux security module intercepting syscalls.
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AppArmor
Why it's wrong here
AppArmor confines programs via path-based profiles, not by filtering the system calls a container may invoke. It is tempting because it is a genuine Linux security module, but seccomp is the mechanism that restricts the syscall set.
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SELinux
Why it's wrong here
SELinux enforces mandatory access control through type labels on files and processes, not syscall filtering. It is tempting because it is a Linux security module that limits privilege, yet seccomp is what restricts which system calls a container can make.
- ✓
seccomp
Why this is correct
seccomp filters the system calls a container may invoke, using a profile to block unused or dangerous calls such as ptrace or mount. This reduces the kernel attack surface, directly enforcing least privilege at the syscall layer rather than through filesystem or capability controls.
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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.