CKS Practice Test 5 — 10 Questions

Question 1

Which command can be used to check if the API server has anonymous authentication enabled?

Accepted Answer

kubectl describe pod kube-apiserver -n kube-system | grep anonymous-auth. The kube-apiserver pod's manifest (or its runtime configuration) contains the `--anonymous-auth` flag. By inspecting the pod's YAML with `kubectl describe pod kube-apiserver -n kube-system` and grepping for `anonymous-auth`, you can see whether the flag is set to `true` (enabled) or `false` (disabled). This is the direct way to check the API server's runtime configuration for anonymous authentication.

Answer

kubectl get clusterrole cluster-admin -o yaml

Answer

kubectl get node -o yaml

Answer

kubectl auth can-i --list --as=system:anonymous

Question 2

Which admission plugin is recommended by the CIS Kubernetes Benchmark to restrict the kubelet's ability to modify nodes?

Accepted Answer

NodeRestriction. The NodeRestriction admission plugin is recommended by the CIS Kubernetes Benchmark to restrict the kubelet's ability to modify nodes. It limits the kubelet's permissions to only modify its own node and its own pods, preventing it from altering other nodes or performing unauthorized operations. This plugin enforces a security boundary by rejecting requests that attempt to modify node labels, taints, or status outside the kubelet's assigned scope.

Answer

PodNodeSelector

Answer

SecurityContextDeny

Answer

AlwaysPullImages

Question 3

A cluster administrator wants to ensure that all pods in a namespace run with the `seccomp` profile set to `RuntimeDefault`. Which OPA Gatekeeper ConstraintTemplate would achieve this?

Accepted Answer

violation[{"msg": "Seccomp profile must be RuntimeDefault"}] { input.review.object.spec.containers[_].securityContext.seccompProfile.type != "RuntimeDefault" }. It uses the Rego rule `input.review.object.spec.containers[_].securityContext.seccompProfile.type != "RuntimeDefault"` to check that every container in the pod has its seccomp profile type set to `RuntimeDefault`. This ensures that any container without the required profile triggers a violation, enforcing the cluster administrator's policy.

Answer

violation[{"msg": "Seccomp profile must be RuntimeDefault"}] { input.review.object.spec.containers[_].securityContext.seccompProfile.type == "Unconfined" }

Answer

violation[{"msg": "Seccomp profile must be RuntimeDefault"}] { input.review.object.spec.containers[_].securityContext.seccompProfile == "RuntimeDefault" }

Answer

violation[{"msg": "Seccomp profile must be RuntimeDefault"}] { input.review.object.spec.securityContext.seccompProfile.type != "RuntimeDefault" }

Question 4

Which TWO of the following are valid audit stages in Kubernetes audit logging?

Accepted Answer

ResponseStarted. Kubernetes audit logging defines four stages: RequestReceived, ResponseStarted, ResponseComplete, and Panic. Among the options, valid stages are A (ResponseStarted), B (Panic), and E (RequestReceived). Since the question asks for exactly two, the selected correct answers are A and E. Both are valid. Option B (Panic) is also a valid stage but is not included as a correct answer for this specific question.

Answer

Panic

Answer

ResponseFinished

Answer

RequestProcessing

Question 5

Which of the following is the best practice for providing sensitive data like passwords to a pod?

Accepted Answer

Mount secrets as volumes into the pod.. Mounting secrets as volumes into the pod is the best practice because it ensures that secrets are stored in a tmpfs (RAM-backed) filesystem, which is never written to disk and is automatically cleaned up when the pod terminates. This approach also allows the kubelet to update the secret contents in the volume without restarting the pod, and it avoids exposing the secret in process listings, logs, or environment variable dumps.

Answer

Use environment variables to inject secrets directly.

Answer

Pass secrets via command-line arguments.

Answer

Hardcode the secret in the container image.

Question 6

Which static analysis tool is specifically designed to evaluate Kubernetes manifests against security best practices?

Accepted Answer

kubesec. Kubesec is a static analysis tool that evaluates Kubernetes manifests (YAML files) against security best practices and provides a security score. Cosign (A) is for container signing and verification, Syft (B) is for generating SBOMs, and Clair (D) is for container vulnerability scanning. Therefore, option C is correct.

Answer

cosign

Answer

syft

Answer

clair

Question 7

An administrator runs 'kubectl describe pod secure-pod' and sees that the pod is in a Pending state with the event 'Error: ImagePullBackOff' and the message 'unauthorized: authentication required'. The image is stored in a private registry. What is the most likely cause?

Accepted Answer

Missing imagePullSecret in the pod spec or in the namespace's default service account. The error 'unauthorized: authentication required' indicates that the kubelet cannot authenticate to the private registry. Kubernetes requires an imagePullSecret, which contains registry credentials (typically a Docker config JSON), to be attached either directly to the pod spec or to the namespace's default service account. Without this secret, the kubelet cannot pull the image, resulting in the ImagePullBackOff state.

Answer

The registry requires TLS 1.3 but the kubelet uses TLS 1.2

Answer

The image tag is misspelled

Answer

The registry hostname is not resolvable

Question 8

Which of the following is a best practice for securing container images?

Accepted Answer

Use minimal base images like distroless or Alpine. Using minimal base images like distroless or Alpine significantly reduces the attack surface by eliminating unnecessary packages, libraries, and utilities that could contain vulnerabilities. Distroless images contain only the application and its runtime dependencies, while Alpine uses musl libc and BusyBox to keep the image size small and minimize the number of Common Vulnerabilities and Exposures (CVEs) that need to be patched.

Answer

Hardcode passwords in Dockerfile as environment variables for convenience

Answer

Use the latest tag for base images to get the newest features

Answer

Run containers as root to simplify permission management

Question 9

Which of the following is a static analysis tool for Kubernetes manifests that can be used to find misconfigurations?

Accepted Answer

Kubesec. Kubesec is a static analysis tool specifically designed to evaluate Kubernetes manifests against a set of built-in security policies. It scans YAML or JSON resource definitions and assigns a risk score based on misconfigurations such as running containers as root, missing resource limits, or insecure capability assignments. This makes it the correct choice for identifying misconfigurations in Kubernetes manifests without executing them.

Answer

Trivy

Answer

Syft

Answer

Cosign

Question 10

Which TWO of the following tools can generate an SBOM (Software Bill of Materials) for a container image?

Accepted Answer

syft. Syft (A) is a CLI tool specifically designed to generate a Software Bill of Materials (SBOM) from container images and filesystems. Cosign attest (B) can also generate an SBOM for a container image using the `--type sbom` flag and attach it as an in-toto attestation. Both tools are capable of producing SBOMs.

Answer

Clair

Answer

kubesec

Answer

Snyk