claude-security-skills

Claude Security Skills

Security skills for Claude Code. Install them once and ask Claude, in plain language, to scan a repo for leaked secrets, review Python code, red-team an LLM for prompt injection, or audit HTTP headers, JWTs, Dockerfiles, CORS, and dependencies. Claude picks the right skill, runs it, and explains what it found.

Everything here runs on the Python standard library — no packages to install, nothing phoning home. The analysis runs offline; only the few skills that need to hit a URL use the network, and only when you ask them to.

Python 3.9+, MIT licensed. Other languages: Español · Русский

$ python skills/secret-scanner/engine.py .
[secret-scanner] 2 potential secret(s) found:

  CRITICAL   src/config.py:14:18
             Stripe secret key [stripe-secret]  value=sk_l...k1L2 (len=32)
  HIGH       src/config.py:12:11
             AWS Access Key ID [aws-access-key-id]  value=AKIA...MPLE (len=20)

Summary: critical=1, high=1

New in 1.1.0: secret-scanner knows Hugging Face, Replicate, Groq, Cohere and DigitalOcean keys, sast-lite flags random used to build tokens, and http-sec-audit gained --advisory for cross-origin isolation. See the changelog.

The skills

Skill	What it does	Engine
secret-scanner	Finds hardcoded API keys, tokens and private keys using vendor patterns plus Shannon-entropy analysis, tuned for few false positives	Custom entropy engine
sast-lite	AST-based static analysis for Python: command injection, eval/exec, insecure deserialization, SQLi, weak crypto, disabled TLS — each tagged with a CWE	Python ast walker
prompt-injection-tester	Red-teams your own LLM app with a categorized payload library and canary detection, then scores resilience 0–100	Canary harness
http-sec-audit	Checks HTTP security headers and cookie flags (CSP, HSTS, SameSite, …) and gives concrete fixes	urllib + pure core
jwt-inspector	Decodes and audits JWTs (alg=none, weak expiry, claim hygiene) and cracks weak HMAC secrets offline	HMAC + checks
dependency-check	Flags known-vulnerable and unpinned deps in requirements.txt, package.json and pyproject.toml; offline DB plus optional OSV.dev	Version matcher
dockerfile-scan	Catches insecure Dockerfile patterns: running as root, :latest base images, curl | sh, remote ADD, baked-in secrets	Dockerfile parser
cors-auditor	Audits CORS config for wildcard-with-credentials, reflected origins, null origin and overly broad methods	Header analyzer

Each skill is self-contained, has its own tests, and exits non-zero when it finds something — so it also works as a CI step.

Install

As a plugin, from inside Claude Code:

/plugin marketplace add NovaCode37/claude-security-skills
/plugin install claude-security-skills

All eight skills arrive together and update with the marketplace.

Or copy them in by hand, which works the same way:

git clone https://github.com/NovaCode37/claude-security-skills.git
cp -r claude-security-skills/skills/* .claude/skills/

Use ~/.claude/skills/ instead to have them in every project. Restart Claude Code and it discovers them from each SKILL.md. There's nothing else to install either way.

If they end up earning their place in your setup, a star helps the next person find them. Installing goes through a clone, so a star is the only part anyone else can see.

Usage

Just ask Claude. For example:

You say	Claude runs
"Any secrets committed in here?"	secret-scanner
"Security-review this Python file."	sast-lite
"Is my AI assistant jailbreakable?"	prompt-injection-tester
"Check example.com's security headers."	http-sec-audit
"Decode and audit this JWT."	jwt-inspector
"Are my dependencies vulnerable?"	dependency-check
"Review my Dockerfile."	dockerfile-scan
"Is my API's CORS safe?"	cors-auditor

Every engine also runs on its own from the command line:

python skills/secret-scanner/engine.py .            --json
python skills/sast-lite/analyzer.py src/            --min-severity high
python skills/prompt-injection-tester/attacker.py   --demo
python skills/http-sec-audit/audit.py https://example.com --min-severity high
python skills/jwt-inspector/inspector.py "<token>"
python skills/dependency-check/checker.py requirements.txt
python skills/dockerfile-scan/scanner.py Dockerfile
python skills/cors-auditor/auditor.py https://api.example.com

In CI

The engines are the same files Claude runs, so a pipeline can call them directly. Nothing to install, so there is no pip install step:

name: security
on: [push, pull_request]

jobs:
  scan:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v5
      - name: Fetch the skills
        run: git clone --depth 1 https://github.com/NovaCode37/claude-security-skills .skills
      - name: Scan
        run: |
          python .skills/skills/secret-scanner/engine.py .
          python .skills/skills/sast-lite/analyzer.py . --min-severity high
          python .skills/skills/dockerfile-scan/scanner.py Dockerfile

Each engine exits 1 when it reports something, so the step fails on a finding. Raise --min-severity to decide what is worth failing over.

Tests

pip install pytest
pytest skills/ -q

227 tests, all offline, run in under a second.

Design principles

• No runtime dependencies. Pure Python 3.9+ stdlib, so the skills run in locked-down CI and are easy to read and audit.
• Offline by default. The analysis logic takes data in and returns findings; network access is optional and explicit.
• Few false positives. Entropy thresholds, keyword anchoring and placeholder allowlists keep the noise down.
• CI-friendly. Consistent exit codes (0 clean, 1 findings, 2 error) and --json on every skill. Every reported finding fails the build, whatever its severity; skills that surface advisory noise take --min-severity so the pipeline can raise the bar.
• Safe by default. Secrets are redacted in output, and the offensive skills are meant for systems you own or are allowed to test.

Contributing

New skills and rules are welcome. The open issues tagged good first issue each name the file to edit and what has to pass before it's done, so you can land one without reading the whole codebase first. CONTRIBUTING.md has the skill template and the conventions.

Also from this project

PRISM — a self-hosted OSINT platform with a web dashboard: domains, IPs, emails, phone numbers and usernames across 22+ modules, with an exposure score, entity graph and HTML/PDF reports.

Legal

These tools are for authorized security testing, learning and defensive work. Only scan systems and data you own or have permission to test. The maintainers aren't responsible for misuse.

License

MIT