- A
The service account can now perform any action across all namespaces, which violates least-privilege.
cluster-admin grants full cluster-level permissions, which is excessive for most service accounts.
- B
The service account can only access resources in the 'default' namespace.
Why wrong: ClusterRoleBindings are cluster-scoped, not namespace-scoped.
- C
No concern; service accounts are allowed to have cluster-admin.
Why wrong: Granting cluster-admin to a service account is a security risk.
- D
The ClusterRoleBinding should be replaced with a RoleBinding.
Why wrong: Even if a RoleBinding is used, if it binds cluster-admin, it still grants full permissions in that namespace? Actually, cluster-admin in a RoleBinding grants permissions across all resources in that namespace, but still excessive. However, the primary concern is the broad permissions.
CKS Cluster Setup and Hardening Practice Question
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 notices a ClusterRoleBinding named 'admin-binding' that binds the 'cluster-admin' ClusterRole to a service account in the 'default' namespace. What security concern does this raise?
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
The service account can now perform any action across all namespaces, which violates least-privilege.
A ClusterRoleBinding grants cluster-wide permissions, and the 'cluster-admin' ClusterRole provides superuser access to perform any action on any resource across all namespaces. Binding this to a service account violates the principle of least privilege because the service account gains unrestricted access to the entire cluster, including sensitive system resources, rather than being limited to only the permissions necessary for its function.
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.
- ✓
The service account can now perform any action across all namespaces, which violates least-privilege.
Why this is correct
cluster-admin grants full cluster-level permissions, which is excessive for most service accounts.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
The service account can only access resources in the 'default' namespace.
Why it's wrong here
ClusterRoleBindings are cluster-scoped, not namespace-scoped.
- ✗
No concern; service accounts are allowed to have cluster-admin.
Why it's wrong here
Granting cluster-admin to a service account is a security risk.
- ✗
The ClusterRoleBinding should be replaced with a RoleBinding.
Why it's wrong here
Even if a RoleBinding is used, if it binds cluster-admin, it still grants full permissions in that namespace? Actually, cluster-admin in a RoleBinding grants permissions across all resources in that namespace, but still excessive. However, the primary concern is the broad permissions.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates may think a service account bound to a ClusterRole is limited to its namespace, or that 'cluster-admin' is acceptable for any service account, when the CKS exam specifically tests the principle of least privilege and the distinction between RoleBindings (namespace-scoped) and ClusterRoleBindings (cluster-scoped).
Detailed technical explanation
How to think about this question
Under the hood, a ClusterRoleBinding binds a ClusterRole (which defines non-namespaced permissions) to subjects, granting those permissions across all namespaces. The 'cluster-admin' ClusterRole is typically aggregated from system:master and includes verbs like '*' on all resources, including sensitive ones like secrets, nodes, and persistent volumes. In a real-world scenario, a compromised service account with cluster-admin could exfiltrate all secrets, delete critical workloads, or modify RBAC rules to maintain persistence, making this a high-severity misconfiguration.
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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Cluster Setup and Hardening — study guide chapter
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FAQ
Questions learners often ask
What does this CKS question test?
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: The service account can now perform any action across all namespaces, which violates least-privilege. — A ClusterRoleBinding grants cluster-wide permissions, and the 'cluster-admin' ClusterRole provides superuser access to perform any action on any resource across all namespaces. Binding this to a service account violates the principle of least privilege because the service account gains unrestricted access to the entire cluster, including sensitive system resources, rather than being limited to only the permissions necessary for its function.
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.
About these practice questions
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: Jun 24, 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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