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.
You are auditing RBAC and find a ClusterRoleBinding named 'admin-binding' that binds the 'cluster-admin' ClusterRole to a service account in the 'default' namespace. What is the security concern?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
It grants too broad permissions to the service account
The 'cluster-admin' ClusterRole grants super-user permissions across the entire cluster, including access to all namespaces and all resources. Binding this role to a service account via a ClusterRoleBinding gives that service account unrestricted cluster-wide privileges, which violates the principle of least privilege. This is a significant security concern because if the service account is compromised, an attacker gains full control over the cluster.
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 binding should be a RoleBinding instead of ClusterRoleBinding
Why it's wrong here
Even with a RoleBinding in a namespace, cluster-admin still grants cluster-wide permissions if bound to a ClusterRole.
✓
It grants too broad permissions to the service account
Why this is correct
Correct. cluster-admin gives superuser access, which should be avoided for service accounts.
Related concept
Read the scenario before looking for a memorised answer.
✗
The service account name must be changed
Why it's wrong here
The name is not a security concern.
✗
The binding is fine as long as the service account is used in the default namespace
Why it's wrong here
No, the wide permissions are still a risk.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates may focus on the binding type (ClusterRoleBinding vs RoleBinding) or namespace usage, rather than recognizing that the core issue is the excessive privileges of the 'cluster-admin' role itself, regardless of how it is bound.
Detailed technical explanation
How to think about this question
The 'cluster-admin' ClusterRole is defined by default in Kubernetes and aggregates permissions from other roles, effectively granting access to all API resources and verbs. A ClusterRoleBinding creates a cluster-scoped binding, meaning the subject (service account) receives permissions across all namespaces. In a real-world scenario, a service account used by a CI/CD pipeline might be granted 'cluster-admin' for convenience, but this violates security best practices; instead, a custom Role or ClusterRole with minimal required permissions should be created and bound via a RoleBinding or ClusterRoleBinding scoped appropriately.
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: It grants too broad permissions to the service account — The 'cluster-admin' ClusterRole grants super-user permissions across the entire cluster, including access to all namespaces and all resources. Binding this role to a service account via a ClusterRoleBinding gives that service account unrestricted cluster-wide privileges, which violates the principle of least privilege. This is a significant security concern because if the service account is compromised, an attacker gains full control over the cluster.
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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