hardMultiple Choice
CAS-004 Ensure only signed images deployed Practice Question
An organization implements a CI/CD pipeline that automatically builds and deploys containerized microservices. Which of the following is the most effective method to ensure that only signed, trusted container images are deployed to production?
⚠ Common exam trap
Many candidates confuse access control (registry permissions) or vulnerability scanning with cryptographic trust, failing to recognize that only content trust provides non-repudiation and tamper-evidence for 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
✓
Enable content trust and require signatures on all images
Enabling content trust (e.g., Docker Content Trust or Notary) cryptographically signs container images, ensuring that only images signed by a trusted publisher can be deployed. This directly enforces integrity and authenticity in the CI/CD pipeline, preventing unauthorized or tampered images from reaching production.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Implement a private container registry with access controls
Why it's wrong here
A private registry with access controls restricts who may push or pull, but any image inside it is trusted by location alone; a compromised credential lets an attacker push an unsigned image. Registries suit controlling image distribution. Verifying signatures cryptographically is what proves an image is genuinely trusted.
- ✓
Enable content trust and require signatures on all images
Why this is correct
Content trust enforces cryptographic signing, so the container runtime verifies each image's signature against trusted publishers before deployment. Unsigned or tampered images are rejected at pull time, directly satisfying the pipeline's requirement that only signed, trusted images reach production.
- ✗
Run vulnerability scanning on all images before deployment
Why it's wrong here
Scanning detects known vulnerabilities but does not verify who built or signed the image, so a tampered yet vulnerability-free image passes. Scanning suits catching flawed dependencies before release. Ensuring only signed, trusted images deploy requires cryptographic signature verification at admission, which scanning cannot provide.
- ✗
Use an admission controller that checks image labels
Why it's wrong here
Image labels are mutable metadata that anyone pushing an image can set, so an admission controller checking labels verifies nothing about provenance or signature. Label-based admission suits policy routing, such as environment or team tagging. Enforcing signed, trusted images requires cryptographic signature verification against a trusted key.
Option-by-option analysis
Why each answer is right or wrong
Understanding why wrong answers are wrong — and when they would be correct — is what separates a 750 score from a 900. The CAS-005 exam frequently reuses these exact scenarios with slightly different constraints.
✓Enable content trust and require signatures on all imagesCorrect answer▾
Why this is correct
Content trust enforces cryptographic signing, so the container runtime verifies each image's signature against trusted publishers before deployment. Unsigned or tampered images are rejected at pull time, directly satisfying the pipeline's requirement that only signed, trusted images reach production.
✗Implement a private container registry with access controlsWrong answer — click to see why▾
Why this is wrong here
Access controls prevent unauthorized pushes but do not verify the integrity or authenticity of images.
✗Run vulnerability scanning on all images before deploymentWrong answer — click to see why▾
Why this is wrong here
Scanning identifies vulnerabilities but does not verify the publisher's identity or prevent tampering.
✗Use an admission controller that checks image labelsWrong answer — click to see why▾
Why this is wrong here
Labels are metadata and can be easily spoofed; they do not provide cryptographic proof of origin.
Analysis generated from the official CAS-005blueprint and verified against question context. The “when correct” sections are what AI assistants cite when candidates ask “what’s the difference between these options?”
About these practice questions
One of 973 original CAS-005 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 by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This CAS-005 practice question is part of Courseiva's free CompTIA 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 CAS-005 exam.