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 TWO of the following are valid ways to reduce the attack surface of a Kubernetes node? (Select 2)
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Restrict hostNetwork, hostPID, and hostIPC access from containers
Restricting hostNetwork, hostPID, and hostIPC access from containers is a valid way to reduce the attack surface of a Kubernetes node because it prevents containers from breaking out of their namespace isolation. When a container uses hostNetwork, it shares the node's network stack, potentially allowing it to sniff traffic or bind to privileged ports. Similarly, hostPID and hostIPC grant access to the host's process table and inter-process communication mechanisms, which can be leveraged for privilege escalation or information disclosure. By default, these should be disabled unless absolutely necessary, as they directly expose host-level resources to the container.
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.
Read the scenario before looking for a memorised answer.
✗
Allow containers to run as root
Why it's wrong here
Running as root increases risk of privilege escalation.
Common exam traps
Common exam trap: answer the scenario, not the keyword
CNCF often tests the misconception that loading all kernel modules is beneficial for compatibility, when in fact it violates the principle of minimizing the attack surface by only loading required modules.
Detailed technical explanation
How to think about this question
Under the hood, Kubernetes uses Linux namespaces (network, PID, IPC) to isolate containers; when hostNetwork is set to true, the container uses the host's network namespace, bypassing iptables rules and network policies that apply to pod networks. In a real-world scenario, a compromised container with hostNetwork access could perform ARP spoofing or capture traffic on the node's interface, while hostPID allows reading /proc entries of other processes, potentially leaking sensitive data like environment variables or credentials. Disabling unnecessary system services (Option D) reduces the node's attack surface by minimizing listening ports and running daemons, which is a standard hardening practice recommended by the CIS Kubernetes Benchmark.
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.
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: Restrict hostNetwork, hostPID, and hostIPC access from containers — Restricting hostNetwork, hostPID, and hostIPC access from containers is a valid way to reduce the attack surface of a Kubernetes node because it prevents containers from breaking out of their namespace isolation. When a container uses hostNetwork, it shares the node's network stack, potentially allowing it to sniff traffic or bind to privileged ports. Similarly, hostPID and hostIPC grant access to the host's process table and inter-process communication mechanisms, which can be leveraged for privilege escalation or information disclosure. By default, these should be disabled unless absolutely necessary, as they directly expose host-level resources to the container.
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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Question Discussion
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