This CKS practice question tests your understanding of cluster setup and hardening. This is a configuration task: choose the command set that satisfies every stated requirement. Small differences — like 'secret' vs 'password' or 'transport input ssh' vs 'all' — change whether the answer is correct. 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.
A developer creates a pod with the following YAML:
apiVersion: v1
kind: Pod
metadata:
name: mypod
spec:
serviceAccountName: default
automountServiceAccountToken: true
containers:
- name: app
image: nginx
What is the security concern with this configuration?
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 token is automatically mounted, potentially providing excessive permissions
Option C is correct because setting `automountServiceAccountToken: true` (or omitting it, as it defaults to true) causes the pod to automatically mount the service account token of the `default` service account into the container. This token can grant excessive permissions if the default service account has been bound to roles with broad access, such as cluster-admin or other privileged RBAC bindings, which is a common misconfiguration. An attacker who compromises the container can then use this token to authenticate to the Kubernetes API server and perform unauthorized actions within 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 pod does not specify resource limits
Why it's wrong here
While important, this is not the main security concern related to service accounts.
✗
The container runs as root
Why it's wrong here
The YAML does not specify securityContext, but the concern is about service account token.
✓
The service account token is automatically mounted, potentially providing excessive permissions
Why this is correct
Automounting the default service account token can be a security risk if the token has broad permissions.
Related concept
Read the scenario before looking for a memorised answer.
✗
The pod uses the 'default' namespace
Why it's wrong here
Using the default namespace is not a security concern per se.
Common exam traps
Common exam trap: answer the scenario, not the keyword
CNCF often tests the misconception that the `default` service account is always safe or that the namespace choice is the primary risk, when in fact the automatic mounting of the service account token—especially when combined with overly permissive RBAC bindings—is the direct security concern.
Detailed technical explanation
How to think about this question
The `automountServiceAccountToken` field controls whether the pod mounts the projected service account token (a JWT) into the container filesystem at `/var/run/secrets/kubernetes.io/serviceaccount/token`. This token is used by the kubelet to authenticate to the Kubernetes API server and is scoped to the service account's RBAC permissions. In real-world scenarios, the default service account is often left with minimal permissions, but if an administrator has inadvertently bound it to a ClusterRole with broad access (e.g., via a RoleBinding or ClusterRoleBinding), the mounted token becomes a critical attack vector. The CKS exam emphasizes disabling this automatic mount for workloads that do not need API access, using `automountServiceAccountToken: false` at the pod or service account level.
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: The service account token is automatically mounted, potentially providing excessive permissions — Option C is correct because setting `automountServiceAccountToken: true` (or omitting it, as it defaults to true) causes the pod to automatically mount the service account token of the `default` service account into the container. This token can grant excessive permissions if the default service account has been bound to roles with broad access, such as cluster-admin or other privileged RBAC bindings, which is a common misconfiguration. An attacker who compromises the container can then use this token to authenticate to the Kubernetes API server and perform unauthorized actions within 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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