- A
MutatingAdmissionWebhook
Why wrong: MutatingAdmissionWebhook can modify resources but is not specifically for image signing verification.
- B
ImagePolicyWebhook
ImagePolicyWebhook is the admission controller that allows integration with external services to verify image signatures.
- C
PodSecurityPolicy (deprecated)
Why wrong: PodSecurityPolicy is deprecated and unrelated to image signing.
- D
ValidatingAdmissionWebhook
Why wrong: While it can be used for custom policies, ImagePolicyWebhook is specifically designed for image policy enforcement.
Question 333 of 997
ImagePolicyWebhook: Enforce Cosign Image Signing in Kubernetes
This CKS practice question tests your understanding of supply chain security. 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 DevOps engineer wants to enforce that all container images running in the cluster are signed using Cosign. Which Kubernetes admission controller is designed for this purpose?
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
✓
ImagePolicyWebhook
The ImagePolicyWebhook admission controller is specifically designed to enforce that container images meet certain criteria, such as being signed with Cosign, by querying an external webhook service that validates image signatures before admitting a pod. It intercepts pod creation requests and checks the image references against a configured policy, making it the correct choice for this Cosign-based image signing enforcement scenario.
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.
- ✗
MutatingAdmissionWebhook
Why it's wrong here
MutatingAdmissionWebhook can modify resources but is not specifically for image signing verification.
- ✓
ImagePolicyWebhook
Why this is correct
ImagePolicyWebhook is the admission controller that allows integration with external services to verify image signatures.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
PodSecurityPolicy (deprecated)
Why it's wrong here
PodSecurityPolicy is deprecated and unrelated to image signing.
- ✗
ValidatingAdmissionWebhook
Why it's wrong here
While it can be used for custom policies, ImagePolicyWebhook is specifically designed for image policy enforcement.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates confuse the generic ValidatingAdmissionWebhook (a Kubernetes admission controller) with the dedicated ImagePolicyWebhook, which is the specific admission controller designed for image policy enforcement in Kubernetes.
Detailed technical explanation
How to think about this question
The ImagePolicyWebhook works by configuring an external webhook server (e.g., using the `--admission-control-config-file` flag) that receives an `ImagePolicyReview` object containing the pod's image references; the webhook returns an `allowed` or `denied` response based on signature verification. Under the hood, Cosign uses public-key cryptography to sign container images stored in OCI-compliant registries, and the webhook can verify these signatures by checking the image's signature blob (e.g., stored as a separate tag like `:sha256-...sig`). A real-world scenario is enforcing that only images signed by a trusted CI/CD pipeline can run in production, preventing supply chain attacks from compromised or untagged images.
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 practitioner preparing for the CKS exam encounters this exact type of scenario on the job. The correct answer here is not the most general option — it is the best answer for the specific constraint described. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Real exam questions reward reading the full scenario before eliminating options, because the constraint defines which answer fits.
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.
- →
Supply Chain Security — study guide chapter
Learn the concepts, then practise the questions
- →
Supply Chain Security practice questions
Targeted practice on this topic area only
- →
All CKS questions
997 questions across all exam domains
- →
Certified Kubernetes Security Specialist CKS study guide
Full concept coverage aligned to exam objectives
- →
CKS practice test guide
How to use practice tests most effectively before exam day
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FAQ
Questions learners often ask
What does this CKS question test?
Supply Chain Security — This question tests Supply Chain Security — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: ImagePolicyWebhook — The ImagePolicyWebhook admission controller is specifically designed to enforce that container images meet certain criteria, such as being signed with Cosign, by querying an external webhook service that validates image signatures before admitting a pod. It intercepts pod creation requests and checks the image references against a configured policy, making it the correct choice for this Cosign-based image signing enforcement scenario.
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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Last reviewed: Jul 4, 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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