This CKS practice question tests your understanding of cluster setup and hardening. Match the stated requirement to the specific cloud service, access model, or configuration option — many options are valid in isolation but not for this scenario. 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.
An administrator runs kubectl get clusterrolebindings and sees a binding named 'system:node'. This binding is part of the legacy node authorization. According to CIS benchmarks, what should be done with it?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Delete it and rely on NodeRestriction and Node authorizer
The 'system:node' ClusterRoleBinding is a legacy binding that grants the 'system:node' cluster role to all nodes, effectively bypassing the Node Authorizer and NodeRestriction admission plugin. The CIS Benchmark for Kubernetes (section 5.1.1) recommends deleting this binding because it allows nodes to have broad, unrestricted access to the API server, which undermines the principle of least privilege. Instead, the Node Authorizer and NodeRestriction plugin should be used to enforce fine-grained, node-specific permissions based on the node's identity and the pods it runs.
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.
✓
Delete it and rely on NodeRestriction and Node authorizer
Why this is correct
CIS recommends removing the system:node binding and using NodeRestriction.
Related concept
Read the scenario before looking for a memorised answer.
✗
Modify the role to include only necessary permissions
Why it's wrong here
The binding is system-defined and should be removed, not modified.
✗
Keep it as it is required for cluster functionality
Why it's wrong here
It is not required; modern clusters use NodeRestriction and node authorizer.
✗
Add a condition to limit it to read-only
Why it's wrong here
ClusterRoleBindings do not support conditions.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates may think the 'system:node' binding is essential for node-to-API-server communication, but in reality, the Node Authorizer and NodeRestriction plugin handle this securely, making the legacy binding a security risk that should be removed.
Detailed technical explanation
How to think about this question
The 'system:node' ClusterRoleBinding was originally used in Kubernetes 1.x to grant nodes access to the API server for operations like watching pods and secrets. However, this binding gives all nodes the same permissions, which violates the principle of least privilege and can allow a compromised node to access resources intended for other nodes. The Node Authorizer, introduced in Kubernetes 1.7, dynamically authorizes node requests based on the node's name and the pods assigned to it, while the NodeRestriction admission plugin ensures that nodes can only modify their own node objects and pods bound to them. Deleting the legacy binding is a critical hardening step per CIS Benchmark 5.1.1, and it is safe to do so as long as the Node Authorizer and NodeRestriction are enabled (which they are by default in modern clusters).
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.
Cluster Setup and Hardening — This question tests Cluster Setup and Hardening — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Delete it and rely on NodeRestriction and Node authorizer — The 'system:node' ClusterRoleBinding is a legacy binding that grants the 'system:node' cluster role to all nodes, effectively bypassing the Node Authorizer and NodeRestriction admission plugin. The CIS Benchmark for Kubernetes (section 5.1.1) recommends deleting this binding because it allows nodes to have broad, unrestricted access to the API server, which undermines the principle of least privilege. Instead, the Node Authorizer and NodeRestriction plugin should be used to enforce fine-grained, node-specific permissions based on the node's identity and the pods it runs.
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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