CKS Supply Chain Security Practice Question
You are asked to generate an SBOM for a container image and attach it as an attestation using cosign. Which two commands would you run in sequence?
⚠ Common exam trap
In CNCF/CKS exams, a common trap is confusing cosign sign (image signature) with cosign attest (attach an attestation). Also, the SBOM must be generated before it can be attached.
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
✓
syft myimage:latest -o spdx > sbom.spdx && cosign attest --type spdx --predicate sbom.spdx myimage:latest
It first uses Syft to generate an SPDX-format SBOM from the container image, then uses cosign attest to attach that SBOM as an in-toto attestation to the image. This sequence satisfies the requirement to generate an SBOM and attach it as an attestation using cosign.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
trivy image --format spdx myimage:latest > sbom.spdx && cosign verify --key cosign.pub myimage:latest
Why it's wrong here
Trivy can generate SBOM, but cosign verify is for verification, not for attaching attestations.
- ✓
syft myimage:latest -o spdx > sbom.spdx && cosign attest --type spdx --predicate sbom.spdx myimage:latest
Why this is correct
This correctly generates an SBOM in SPDX format and attaches it as an in-toto attestation.
- ✗
cosign sign --key cosign.key myimage:latest && syft myimage:latest -o spdx
Why it's wrong here
Signing first is unnecessary and the order is wrong; SBOM generation should precede attestation.
- ✗
crane ls myimage:latest && cosign attest --type spdx --predicate sbom.spdx myimage:latest
Why it's wrong here
crane ls lists tags, it does not generate an SBOM.
Go deeper
Related to this question
Learn chapter
Supply Chain Security: Container Image Security
Key term
Image Signing and Verification
Image signing and verification is the process of digitally signing a container image to prove its origin and integrity, and then checking that signature before using the image to ensure it was not tampered with.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
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.