- A
PodSecurityPolicy
Why wrong: PodSecurityPolicy is deprecated and not related to image signing; it controls pod security contexts.
- B
MutatingAdmissionWebhook
Why wrong: MutatingAdmissionWebhook can modify resources but is not specifically designed for image signature verification.
- C
ImagePolicyWebhook
ImagePolicyWebhook allows an external webhook to validate images based on signatures.
- D
ValidatingAdmissionWebhook
Why wrong: ValidatingAdmissionWebhook can validate resources but is not specifically for image signatures; ImagePolicyWebhook is the dedicated one.
Question 832 of 997
ImagePolicyWebhook: Enforcing Image Signature Verification
This CKS practice question tests your understanding of supply chain security. 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.
A security admin wants to ensure that only images signed with a specific key can run in the cluster. Which admission controller should be enabled?
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 allows a cluster to enforce that only container images signed with a specific key can run. It intercepts pod creation requests and queries an external webhook to verify the image signature before admitting the pod. This directly meets the requirement of restricting execution to signed images.
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.
- ✗
PodSecurityPolicy
Why it's wrong here
PodSecurityPolicy is deprecated and not related to image signing; it controls pod security contexts.
- ✗
MutatingAdmissionWebhook
Why it's wrong here
MutatingAdmissionWebhook can modify resources but is not specifically designed for image signature verification.
- ✓
ImagePolicyWebhook
Why this is correct
ImagePolicyWebhook allows an external webhook to validate images based on signatures.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
ValidatingAdmissionWebhook
Why it's wrong here
ValidatingAdmissionWebhook can validate resources but is not specifically for image signatures; ImagePolicyWebhook is the dedicated one.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The distinction between generic webhook controllers (MutatingAdmissionWebhook and ValidatingAdmissionWebhook) and the purpose-built ImagePolicyWebhook is a common point of confusion. Candidates often mistakenly choose a generic webhook when the question explicitly asks for the admission controller designed for image signature enforcement.
Detailed technical explanation
How to think about this question
ImagePolicyWebhook works by configuring an external webhook server (e.g., using the `kube-image-bouncer` or a custom service) that checks image signatures via mechanisms like Docker Content Trust or Notary. The admission controller sends an ImageReview request to the webhook, which returns an allowed/denied response based on the signature validation. A subtle behavior is that the webhook must be highly available, as a failure to reach it can block all pod creation unless the `failurePolicy` is set to `Ignore` (which would bypass the check).
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 allows a cluster to enforce that only container images signed with a specific key can run. It intercepts pod creation requests and queries an external webhook to verify the image signature before admitting the pod. This directly meets the requirement of restricting execution to signed images.
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 →
Same concept, more angles
1 more ways this is tested on CKS
These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. A security admin runs 'trivy image --severity CRITICAL,HIGH myrepo/myapp:latest' and sees many CVEs. The admin wants to ensure that only images with no CRITICAL or HIGH severity vulnerabilities are deployed to the cluster. Which admission controller should be configured to enforce this policy?
medium- A.PodSecurityPolicy
- B.ValidatingAdmissionWebhook
- C.MutatingAdmissionWebhook
- ✓ D.ImagePolicyWebhook
Why D: The ImagePolicyWebhook admission controller is specifically designed to evaluate container images against an external policy backend before they are admitted into the cluster. By configuring it to reject images with CRITICAL or HIGH severity vulnerabilities (as reported by Trivy), the admin can enforce that only compliant images are deployed. This controller intercepts Pod creation requests and queries an external webhook to decide whether to allow or deny the image based on the policy.
Keep practising
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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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