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.
You are tasked with reducing the attack surface on a Kubernetes node. Which of the following actions is LEAST effective for hardening the node itself?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue: "least"
Why it matters: You want the option with minimum overhead, fewest steps, or lowest impact — not the most feature-rich or comprehensive answer.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Drop the NET_RAW capability from all containers running on the node
Option C is the least effective for hardening the node itself because dropping NET_RAW from containers is a container-level security control (e.g., via Pod Security Standards or seccomp), not a node-level hardening measure. Node hardening focuses on the host OS and Kubernetes components, not container capabilities. While it reduces attack surface for containers, it does not directly secure the node's kernel, services, or network access.
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.
✗
Restrict SSH access to the node using firewall rules
Why it's wrong here
Limiting SSH access reduces the risk of unauthorized access to the node.
✗
Disable unnecessary system services (e.g., telnet, rsh) on the node
Why it's wrong here
Disabling unused services reduces attack vectors on the node.
✓
Drop the NET_RAW capability from all containers running on the node
Why this is correct
This is a container-level hardening measure. While beneficial, it does not directly harden the node itself.
Clue confirmation
The clue word "least" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
✗
Apply the latest security patches to the host kernel
Why it's wrong here
Patching the kernel fixes known vulnerabilities, directly hardening the node.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates confuse container-level security controls (like dropping capabilities) with node-level hardening, assuming any security measure applied to containers also hardens the underlying node, when in fact node hardening requires direct OS and infrastructure changes.
Detailed technical explanation
How to think about this question
Node hardening typically involves OS-level controls such as kernel hardening (e.g., sysctl settings, AppArmor/SELinux), disabling unused ports and services, and applying patches. Container capabilities like NET_RAW are managed via container runtime security contexts (e.g., `securityContext.capabilities.drop` in Pod specs) and are enforced by the kernel's capability system, but they do not affect the node's own exposed services or kernel vulnerabilities. In a real-world scenario, an attacker who gains access to a node via an unpatched kernel exploit would not be stopped by dropped container capabilities.
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 small business has 20 workstations on the 192.168.1.0/24 network and one public IP from its ISP. The router uses PAT (NAT overload) so all 20 devices share one public address using different source ports. NAT questions test whether you understand the four address terms and which direction each translation applies.
Related glossary terms
Concepts from this question explained
These glossary pages explain the core terms tested in this CKS question in full detail.
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: Drop the NET_RAW capability from all containers running on the node — Option C is the least effective for hardening the node itself because dropping NET_RAW from containers is a container-level security control (e.g., via Pod Security Standards or seccomp), not a node-level hardening measure. Node hardening focuses on the host OS and Kubernetes components, not container capabilities. While it reduces attack surface for containers, it does not directly secure the node's kernel, services, or network access.
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.
Are there clue words in this question I should notice?
Yes — watch for: "least". You want the option with minimum overhead, fewest steps, or lowest impact — not the most feature-rich or comprehensive answer.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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Question Discussion
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