Vulnetix Container Scan Skill

Use when

• Pre-build: scan a Dockerfile for misconfigurations and base-image CVEs.
• PR review: detect EOL base images, missing USER, root processes, exposed secrets.
• --image registry/img:tag: scan a built image for installed-package CVEs via Trivy/Grype if available.
• Compose with Syft to produce a container SBOM (CycloneDX JSON).
• Hardening checklist: USER directive present, healthcheck defined, pinned versions, layer minimisation.

Don't use for

• Source-code SAST — use sast-scan.
• Cloud-config (Terraform / k8s manifests) — use iac-scan.
• Vulnetix CLI itself does not pull images; for --image you need binaries.docker or binaries.podman.

Conventions

Follows skills/_lib/contract.md. In short: use the vulnetix_* MCP tools when the agent has them and the CLI otherwise — both shape their own output, so there is no jq step any more. Independent calls go out as concurrent Bash tool calls in one message. One trailing suggestion, not a playbook. See the contract for surface selection, output style and memory writes.

Step 1: Load capabilities

Read .vulnetix/capabilities.yaml. Note: binaries.{docker,podman,trivy,grype,syft}, repo.{dockerfile,containerfile,compose,docker_compose}. If no container artifacts found AND no --image argument, abort with a one-liner.

Step 2: Run Vulnetix container analysis

vulnetix containers --paths "$DOCKERFILE_PATHS" -o json > .vulnetix/containers.${TIMESTAMP}.json

Or:

vulnetix scan --enable-containers --paths "$DOCKERFILE_PATHS" -o json

Captures: base-image risk, EOL bases, exposed secrets, missing USER, root processes, missing healthchecks, vulnerable system packages.

Step 3: Compose with installed scanners (conditional)

For each available binary:

• binaries.trivy: true →

  trivy config "$DOCKERFILE_PATH" --format json > .vulnetix/containers/trivy.config.json
  trivy image "$IMAGE" --format json > .vulnetix/containers/trivy.image.json   # if --image

• binaries.grype: true AND --image →

  grype "$IMAGE" -o json > .vulnetix/containers/grype.json

• binaries.syft: true AND --image →

  syft "$IMAGE" -o cyclonedx-json > .vulnetix/containers/${IMAGE//[\/:]/_}.cdx.json

Merge findings into a unified table; de-dup by CVE+package.

Step 4: Render

| Severity | Source | Issue | File / Layer | Fix |
| Critical | trivy  | CVE-... in libxml2 2.9.10 | layer 3 | bump base to alpine:3.19 |

Plus a "Hardening checklist" section: USER directive, healthcheck, pinned versions, reduced layers.

Memory update

Write .vulnetix/containers/<timestamp>.summary.yaml with finding counts by severity.

Edge cases & gotchas

• Trivy/Grype/Syft are optional. If absent, the skill runs Vulnetix-only checks (Dockerfile lint + base-image known-CVE list).
• Compose files (docker-compose.yml) are scanned per-service; results are split per service-name.
• --image requires the image to be pullable (registry auth via docker login / podman login first).
• Trivy DB updates can take 30s on first run; subsequent invocations are cached.
• EOL base-image detection uses vulnetix vdb product — same eol-status as eol-check.
• Layer reordering recommendations are heuristic; if your build has a legitimate reason for the current order, the recommendation may be incorrect.