KCSA Kubernetes Threat Model Practice Question
A security engineer is analyzing supply chain risks for container images. An unsigned image from an untrusted public registry is pulled into a secure cluster. Which Admission Controller plugin can be leveraged to prevent the deployment of unsigned container images?
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
✓
ValidatingAdmissionWebhook executing a policy engine integrated with Cosign image signature verification
ValidatingAdmissionPolicy or admission webhook controllers like OPA Gatekeeper or Kyverno integrated with cryptographic signature verification (such as Cosign) are used to enforce image signing.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
NamespaceLifecycle admission plugin
Why it's wrong here
NamespaceLifecycle prevents deletion of system namespaces and ensures pods are not created in terminating namespaces.
- ✓
ValidatingAdmissionWebhook executing a policy engine integrated with Cosign image signature verification
Why this is correct
Using a validating webhook with a policy engine allows checking cryptographic signatures against a trusted public key before allowing pod creation.
- ✗
DefaultStorageClass admission controller
Why it's wrong here
DefaultStorageClass manages PersistentVolume claims, not image supply chain security.
- ✗
LimitRanger
Why it's wrong here
LimitRanger enforces resource constraints within a namespace, not image provenance.
About these practice questions
One of 320 original KCSA practice questions on Courseiva, each with a full explanation and wrong-answer analysis — not exam dumps or protected exam content. Learn why practice questions differ from exam dumps →
JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed August 2026 · checked against the official CNCF / Linux Foundation exam blueprint
This KCSA practice question is part of Courseiva's free CNCF / Linux Foundation 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 KCSA exam.