- A
Set hostNetwork: true for better network performance
Why wrong: This exposes the host network to the container, increasing attack surface.
- B
Set securityContext.runAsNonRoot: true
Prevents running as root, reducing the impact of container escape.
- C
Drop all capabilities and add only required ones
This follows the principle of least privilege.
- D
Enable audit logging for all API requests
Why wrong: Audit logging is important for security monitoring but does not directly reduce attack surface.
- E
Run containers with read-only root filesystem
Prevents write access to the container filesystem, reducing risk of malware.
Question 347 of 997
How to Reduce Container Attack Surface in Kubernetes
This CKS practice question tests your understanding of system hardening. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
Which THREE of the following actions help reduce the attack surface of containers? (Select 3 correct answers)
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
✓
Set securityContext.runAsNonRoot: true
Setting `securityContext.runAsNonRoot: true` forces the container to run with a user ID that is not 0 (root). This prevents an attacker who gains code execution inside the container from having root privileges, which would otherwise allow them to escape the container, modify system binaries, or perform privileged operations. It is a fundamental principle of least privilege and directly reduces the attack surface by limiting the damage a compromised container can do.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Set hostNetwork: true for better network performance
Why it's wrong here
This exposes the host network to the container, increasing attack surface.
- ✓
Set securityContext.runAsNonRoot: true
Why this is correct
Prevents running as root, reducing the impact of container escape.
Related concept
Read the scenario before looking for a memorised answer.
- ✓
Drop all capabilities and add only required ones
Why this is correct
This follows the principle of least privilege.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
Enable audit logging for all API requests
Why it's wrong here
Audit logging is important for security monitoring but does not directly reduce attack surface.
- ✓
Run containers with read-only root filesystem
Why this is correct
Prevents write access to the container filesystem, reducing risk of malware.
Related concept
Read the scenario before looking for a memorised answer.
Common exam traps
Common exam trap: answer the scenario, not the keyword
A common pitfall in this exam is confusing security controls that directly reduce the attack surface (e.g., dropping capabilities, read-only filesystem, non-root user) with controls that provide visibility or performance improvements (e.g., audit logging, hostNetwork). Candidates often incorrectly select options that enhance monitoring or speed rather than those that harden the container.
Detailed technical explanation
How to think about this question
Under the hood, when `runAsNonRoot: true` is set, the container runtime (e.g., containerd or CRI-O) verifies that the user ID in the container's user namespace is non-zero. If the image specifies a USER directive with UID 0, the Pod will fail to start. This is enforced by the `RunAsNonRoot` field in the PodSecurityContext, which is part of the Kubernetes Pod Security Standards (PSS) baseline policy. In a real-world scenario, a misconfigured container running as root could be exploited via a kernel vulnerability (e.g., CVE-2022-0185) to gain host access, whereas a non-root container would have significantly reduced impact.
KKey Concepts to Remember
- Read the scenario before looking for a memorised answer.
- Find the constraint that changes the correct option.
- Eliminate answers that are true in general but not in this case.
TExam Day Tips
- Watch for words such as best, first, most likely and least administrative effort.
- Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A junior network technician can log in to a core router but cannot reach the enable prompt or configuration mode. The AAA server is authenticating the login — but the authorisation policy only grants privilege level 1, not 15. Authentication (who you are) is working; authorisation (what you can do) is not.
What to study next
Got this wrong? Here's your next step.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
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FAQ
Questions learners often ask
What does this CKS question test?
System Hardening — This question tests System Hardening — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Set securityContext.runAsNonRoot: true — Setting `securityContext.runAsNonRoot: true` forces the container to run with a user ID that is not 0 (root). This prevents an attacker who gains code execution inside the container from having root privileges, which would otherwise allow them to escape the container, modify system binaries, or perform privileged operations. It is a fundamental principle of least privilege and directly reduces the attack surface by limiting the damage a compromised container can do.
What should I do if I get this CKS question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
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Last reviewed: Jul 4, 2026
This CKS practice question is part of Courseiva's free CNCF 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 CKS exam.
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