- A
FROM gcr.io/distroless/base:latest
Distroless images contain only the necessary runtime dependencies, greatly reducing the attack surface.
- B
FROM alpine:latest
Why wrong: Alpine is minimal but still includes a package manager and some utilities; distroless is more minimal.
- C
FROM scratch
Why wrong: Scratch is empty but requires manually adding all binaries, which is often impractical; distroless is a better balance.
- D
FROM ubuntu:20.04
Why wrong: Pinning a version is good practice but does not minimize the number of packages; Ubuntu still has many components.
Question 644 of 997
Minimal Base Image: Distroless for Reduced Attack Surface
This CKS practice question tests your understanding of supply chain security. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. 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 Dockerfile with 'FROM ubuntu:latest'. The security team recommends using a minimal base image. Which change minimizes the attack surface?
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
✓
FROM gcr.io/distroless/base:latest
The `gcr.io/distroless/base:latest` image is a minimal, language-specific base image that contains only the essential runtime dependencies (e.g., glibc, libssl) and no package manager, shell, or utilities. This drastically reduces the attack surface by eliminating unnecessary binaries and tools that could be exploited. In contrast, `ubuntu:latest` includes a full userland with apt, bash, and other utilities, increasing the potential for privilege escalation or supply chain attacks.
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.
- ✓
FROM gcr.io/distroless/base:latest
Why this is correct
Distroless images contain only the necessary runtime dependencies, greatly reducing the attack surface.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
FROM alpine:latest
Why it's wrong here
Alpine is minimal but still includes a package manager and some utilities; distroless is more minimal.
- ✗
FROM scratch
Why it's wrong here
Scratch is empty but requires manually adding all binaries, which is often impractical; distroless is a better balance.
- ✗
FROM ubuntu:20.04
Why it's wrong here
Pinning a version is good practice but does not minimize the number of packages; Ubuntu still has many components.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The CKS exam often tests the misconception that `alpine:latest` is the most minimal secure base image, but distroless images are even more minimal because they strip out the shell and package manager entirely, which is the key differentiator for attack surface reduction.
Detailed technical explanation
How to think about this question
Distroless images are built using Bazel and contain only the bare minimum filesystem (e.g., /etc, /lib, /usr/lib) with specific runtime dependencies like glibc and libssl, but no shell or package manager. This means that even if an attacker gains code execution, they cannot use commands like `apt` or `bash` to pivot or download additional tools. In a real-world scenario, a container running a Go or Python application on distroless/base would have no `curl` or `wget`, severely limiting post-exploitation capabilities.
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.
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
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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: FROM gcr.io/distroless/base:latest — The `gcr.io/distroless/base:latest` image is a minimal, language-specific base image that contains only the essential runtime dependencies (e.g., glibc, libssl) and no package manager, shell, or utilities. This drastically reduces the attack surface by eliminating unnecessary binaries and tools that could be exploited. In contrast, `ubuntu:latest` includes a full userland with apt, bash, and other utilities, increasing the potential for privilege escalation or supply chain attacks.
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 →
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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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