Scanning Docker Images With Trivy

What it does

When your agent uses it

• Gating a specific image
• Wiring an image scan into CI/CD
• Checking an image during an incident investigation
• Cluster-wide scanning

Example prompts

• “Use the scanning-docker-images-with-trivy skill to scan a Docker image with Trivy for vulnerabilities in OS packages and language dependencies…”
• “/scanning-docker-images-with-trivy”

Requirements

• Python 3
• Docker

Workflow steps

7 steps, taken from the step headings in SKILL.md.

1. 1Install Trivy
2. 2Basic Image Scanning
3. 3Advanced Scanning Options
4. 4Scanning Kubernetes Manifests
5. 5CI/CD Integration
6. 6Policy Enforcement with .trivyignore
7. 7Scan Private Registry Images

What it can do on your machine

Read from SKILL.md and the folder at commit 54a7988. It shows what the files ask for, not the result of running them.

• Tool permissions

  Pre-approves nothing: there is no allowed-tools line, so your agent's usual permission prompts apply.

  From allowed-tools in the SKILL.md frontmatter.

• Runs code

  Ships 2 files in scripts/ (Python), which the agent can run.

  Shell commands in SKILL.md call:

  • trivy
  • docker
  • apt-get
  • wget
  • brew
  • aws

  From the folder's file list and the shell code blocks in SKILL.md.

• Network

  Hosts in commands or code, which the agent is likely to contact:

  • aquasecurity.github.io

  Also links to:

  • github.com
  • trivy.dev
  • aquasec.com

  From URLs in SKILL.md, links to its own repository left out.

• Credentials

  Names these keys or tokens, usually read from environment variables:

  • TRIVY_PASSWORD

  From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.

Context cost

Scanning Docker Images With Trivy loads about 1.9k tokens when it runs, and up to ~3.9k if it reads all its reference files. Until then it costs about 159 tokens; SKILL.md has 254 words of instructions outside code blocks.

Always · name and description, kept in context so the agent knows when to use it

~159

When it runs · the whole SKILL.md, loaded when a task matches

~1.9k

With references · SKILL.md plus every file in references/, read only if the agent opens them

~3.9k

Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.

Safety

• NoteRuns commands with sudoSKILL.md:92

  sudo apt-get install wget apt-transport-https gnupg lsb-release

• NoteRuns commands with sudoSKILL.md:93

  vy-repo/deb/public.key | gpg --dearmor | sudo tee /usr/share/keyrings/trivy.gpg > /dev/null

• NoteRuns commands with sudoSKILL.md:94

  rivy-repo/deb $(lsb_release -sc) main" | sudo tee -a /etc/apt/sources.list.d/trivy.list

• NoteRuns commands with sudoSKILL.md:95

  sudo apt-get update && sudo apt-get install trivy

• WarningMentions a credentials file (SSH keys, cloud or package-manager tokens)SKILL.md:238

  # Docker Hub (uses ~/.docker/config.json)

Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); the scripts in this folder are not scanned.

SKILL.md

The full file from mukul975/Anthropic-Cybersecurity-Skills at commit 54a7988, republished under its Apache-2.0 licence (© mukul975). 254 words, ~1,897 tokens.

name

scanning-docker-images-with-trivy

description

Scans a Docker image with Trivy for vulnerabilities in OS packages and language dependencies, misconfiguration, exposed secrets, and licence violations, emitting SARIF, CycloneDX, or SPDX output. Use when scanning or gating a specific image, wiring an image scan into CI/CD, or checking an image during an incident investigation. Keywords: Trivy, image scan, --severity, --exit-code, SARIF, ignore file, .trivyignore. Do not use for cluster-wide scanning or non-image targets - use performing-container-security-scanning-with-trivy; when the toolchain is Grype use scanning-container-images-with-grype.

domain

cybersecurity

subdomain

container-security

tags

containers, docker, security, trivy, vulnerability-scanning

version

1.0

author

mahipal

license

Apache-2.0

nist_csf

PR.PS-01, PR.IR-01, ID.AM-08, DE.CM-01

mitre_attack

T1610, T1611, T1609, T1525, T1190

# Linux (apt)
sudo apt-get install wget apt-transport-https gnupg lsb-release
wget -qO - https://aquasecurity.github.io/trivy-repo/deb/public.key | gpg --dearmor | sudo tee /usr/share/keyrings/trivy.gpg > /dev/null
echo "deb [signed-by=/usr/share/keyrings/trivy.gpg] https://aquasecurity.github.io/trivy-repo/deb $(lsb_release -sc) main" | sudo tee -a /etc/apt/sources.list.d/trivy.list
sudo apt-get update && sudo apt-get install trivy

# macOS
brew install trivy

# Docker
docker pull aquasecurity/trivy:latest

# Scan a public image
trivy image python:3.12-slim

# Scan with severity filter
trivy image --severity CRITICAL,HIGH nginx:latest

# Ignore unfixed vulnerabilities
trivy image --ignore-unfixed alpine:3.19

# Scan local image
docker build -t myapp:latest .
trivy image myapp:latest

# Scan from tar archive
docker save myapp:latest -o myapp.tar
trivy image --input myapp.tar

# All scanners (vuln + misconfig + secret + license)
trivy image --scanners vuln,misconfig,secret,license myapp:latest

# Generate SBOM in CycloneDX format
trivy image --format cyclonedx --output sbom.cdx.json myapp:latest

# Generate SBOM in SPDX format
trivy image --format spdx-json --output sbom.spdx.json myapp:latest

# JSON output for programmatic processing
trivy image --format json --output results.json myapp:latest

# SARIF output for GitHub Security tab
trivy image --format sarif --output results.sarif myapp:latest

# Template-based output
trivy image --format template --template "@contrib/html.tpl" --output report.html myapp:latest

# Scan specific layers only
trivy image --list-all-pkgs myapp:latest

# Scan Dockerfile for misconfigurations
trivy config Dockerfile

# Scan Kubernetes manifests
trivy config k8s-deployment.yaml

# Scan Helm charts
trivy config ./helm-chart/

# Scan Terraform files
trivy config ./terraform/

# GitHub Actions
name: Trivy Container Scan
on: push

jobs:
  scan:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4

      - name: Build image
        run: docker build -t myapp:${{ github.sha }} .

      - name: Run Trivy vulnerability scanner
        uses: aquasecurity/trivy-action@master
        with:
          image-ref: myapp:${{ github.sha }}
          format: sarif
          output: trivy-results.sarif
          severity: CRITICAL,HIGH
          exit-code: 1

      - name: Upload Trivy scan results
        uses: github/codeql-action/upload-sarif@v3
        if: always()
        with:
          sarif_file: trivy-results.sarif

      - name: Generate SBOM
        uses: aquasecurity/trivy-action@master
        with:
          image-ref: myapp:${{ github.sha }}
          format: cyclonedx
          output: sbom.cdx.json

# GitLab CI
trivy-scan:
  stage: security
  image:
    name: aquasecurity/trivy:latest
    entrypoint: [""]
  script:
    - trivy image --exit-code 1 --severity CRITICAL,HIGH
        --format json --output gl-container-scanning-report.json
        $CI_REGISTRY_IMAGE:$CI_COMMIT_SHA
  artifacts:
    reports:
      container_scanning: gl-container-scanning-report.json

# .trivyignore - Ignore specific CVEs with expiry
# Accepted risk: low-impact vulnerability in dev dependency
CVE-2023-12345 exp:2025-06-01

# False positive: not exploitable in our configuration
CVE-2024-67890

# Vendor will not fix
CVE-2023-11111

# Docker Hub (uses ~/.docker/config.json)
trivy image myregistry.azurecr.io/myapp:latest

# ECR
aws ecr get-login-password --region us-east-1 | docker login --username AWS --password-stdin <account>.dkr.ecr.us-east-1.amazonaws.com
trivy image <account>.dkr.ecr.us-east-1.amazonaws.com/myapp:latest

# GCR
trivy image gcr.io/my-project/myapp:latest

# With explicit credentials
TRIVY_USERNAME=user TRIVY_PASSWORD=pass trivy image registry.example.com/myapp:latest

# Verify Trivy installation
trivy version

# Update vulnerability database
trivy image --download-db-only

# Quick scan with table output
trivy image --severity CRITICAL python:3.12

# Verify no CRITICAL vulnerabilities
trivy image --exit-code 1 --severity CRITICAL myapp:latest
echo "Exit code: $?"  # 0 = no vulns, 1 = vulns found

© mukul975, Apache-2.0. Rendered from Markdown: HTML in the file is shown as text, images as links, and headings moved down two levels. Raw file

Files

SKILL.md and 7 other files (scripts, references, assets) in skills/scanning-docker-images-with-trivy of mukul975/Anthropic-Cybersecurity-Skills.

• SKILL.md
• LICENSE
• assets/template.md
• references/api-reference.md
• references/standards.md
• references/workflows.md
• scripts/agent.py
• scripts/process.py

Open the folder on GitHubat commit 54a7988