Container Scan

---
name: container-scan
description: 'Dockerfile / Containerfile / compose analysis plus optional Trivy / Grype / Syft composition when those binaries are present. Use when reviewing a Dockerfile PR, gating `docker build`, building an image SBOM, evaluating base-image risk, or auditing a registry image for CVEs.'
license: Apache-2.0
allowed-tools: Bash(vulnetix:*) Read Grep Glob Bash(syft:*) Bash(grype:*) Bash(trivy:*)
argument-hint: "[--paths Dockerfile1 Dockerfile2] [--image registry/img:tag]"
user-invocable: true
model: sonnet
metadata:
  outputBudget: short
  cooldown: per-session
  chain: "verify-fix"
---
# 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

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

Or:

```bash
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` →
  ```bash
  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` →
  ```bash
  grype "$IMAGE" -o json > .vulnetix/containers/grype.json
  ```
- `binaries.syft: true` AND `--image` →
  ```bash
  syft "$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.