security-audit-skill
by cloudflare
A coding-agent skill for multi-phase security audits with independently verified, machine-readable findings
71,783stars
4,779forks
JavaScript
Added 11/13/2026
Available after the catalog security scan passes.
⚠️ Third-Party Software Notice
This skill is third-party open-source software developed and hosted independently on GitHub. SkillsLLM is an informational directory and does not control or maintain the underlying repository.
Any security checks, ratings, or warnings displayed by SkillsLLM are automated and limited in scope. They do not constitute a security certification or guarantee that the software is safe, error-free, or free from malicious code, vulnerabilities, compromised dependencies, or prompt-injection risks.
Review the source code, permissions, dependencies, and configuration before installing or running any third-party skill. Use is at your own risk. To the maximum extent permitted by applicable law, SkillsLLM is not liable for losses arising from third-party software.
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Maintainer of this skill?
Installation
# Add to your Claude Code skills
git clone https://github.com/cloudflare/security-audit-skillGetting Started
Guides for using ai agents skills like security-audit-skill.
- Caveman: Cut Claude Token Use by 65%How agent-side prompt compression works, when to use it, and when not to.
- How to Test an AI Skill: A Practical Guide to EvalsEvaluate skills with realistic fixtures, a baseline, and repeatable checks.
- Getting Started with AI SkillsFirst-time install walkthrough for Claude Code, Codex CLI, and ChatGPT.
security-audit
A coding-agent skill that turns your agent into a security auditor. It orchestrates isolated agents through reconnaissance, coverage-led hunting, candidate validation, structured output, independent record verification, and target-neutral reporting.
This is the skill that seeded Cloudflare's vulnerability discovery harness, described in Build your own vulnerability harness. The harness grew into a multi-stage, fleet-wide system; this skill is the single-repo starting point it evolved from.
What it does
The skill runs a structured audit in six phases:
- Reconnaissance -- map architecture, trust boundaries, input surfaces, prior evidence, and deterministic coverage in
architecture.mdandcoverage-ledger.json. - Coverage-led hunting -- assign isolated hunters from ledger units, record their checks, and use coverage critics to find gaps.
- Candidate validation -- give every unique candidate to a fresh verifier that tries to disprove it.
- Structured output -- write
confirmed,needs_validation, andrejectedrecords tofindings.jsonand validate them againstreport-schema.json. - Independent record verification -- fresh agents verify final source claims. Material replacements receive another independent verifier.
- Target-neutral reporting -- derive
REPORT.md,FINDINGS-DETAIL.md, andNEEDS-VALIDATION.mdfrom the verified records and coverage ledger.
The parent runs validate-coverage-ledger.cjs after creating the ledger and after each later ledger update. It runs validate-findings.cjs in Phase 4 and again after every Phase 5 replacement.
The verdicts are distinct: confirmed has a complete source trace and bounded observed result, needs_validation has an exact unresolved fact and no severity, and rejected records a disproved candidate.
Multiple runs against the same repo are additive. The skill uses prior ledgers and findings to target gaps, revalidate changed source, and carry forward current-source evidence without treating stale or unresolved work as covered.
Files
| File | Purpose |
|---|---|
SKILL.md |
Setup, core principles, platform terminology, workflow overview, and audit anti-patterns |
RECONNAISSANCE.md |
Phase 1 reconnaissance prompts and synthesis instructions |
HUNTING.md |
Phase 2 orchestration, hunting methodology, and validation rules |
ATTACK-CLASSES.md |
Core, wildcard, and obvious-things attack prompts |
MEMORY-SAFETY-AND-BINARY.md |
Memory-safety, binary, and kernel hunting classes for native targets |
AI-AND-LLM.md |
Prompt-injection, agent/tool, and output-handling hunting classes for LLM-backed targets |
WEB-PROTOCOL-AND-AUTH.md |
HTTP request-framing, cache, and authentication-protocol hunting classes for HTTP-protocol and auth targets |
CLIENT-SIDE.md |
DOM-injection, messaging-trust, UI-redress, and prototype-pollution hunting classes for client-side/browser targets |
SUPPLY-CHAIN-AND-RELEASE.md |
Dependency, CI, release, signing, update, plugin, and extension hunting classes |
CLOUD-AND-DEPLOYMENT.md |
IAM, infrastructure-as-code, container, serverless, ingress, and runtime-configuration hunting classes |
PROTOCOLS-RPC-AND-MESSAGING.md |
RPC, serialization, queue, broker, webhook, and streaming-protocol hunting classes |
RESOURCE-EXHAUSTION-AND-AVAILABILITY.md |
Shared resource, quota, queue, worker, and operator-spend hunting classes |
DATA-ISOLATION-AND-LIFECYCLE.md |
Tenant isolation, cache, search, export, backup, migration, deletion, and restore hunting classes |
DESKTOP-MOBILE-AND-LOCAL-IPC.md |
Native app, deep-link, webview, exported-component, helper, daemon, and local-IPC hunting classes |
VALIDATION-AND-REPORTING.md |
Phases 3–6 candidate validation, structured output, record verification, and reporting |
report-schema.json |
JSON schema for all three findings.json verdicts |
validate-findings.cjs |
Zero-dependency validator for findings.json in Phases 4 and 5 |
validate-findings.test.cjs |
Findings-validator tests and producer-compatible fixture checks |
validate-coverage-ledger.cjs |
Zero-dependency validator for coverage-ledger.json in Phases 1–5 |
validate-coverage-ledger.test.cjs |
Coverage-ledger validator tests |
Installation
Install the skill with the Skills CLI:
npx skills add https://github.com/cloudflare/security-audit-skill \
--skill security-audit
Use --global for a user-level installation:
npx skills add https://github.com/cloudflare/security-audit-skill \
--skill security-audit \
--global
Run npx skills --help for agent-selection and non-interactive options.
Usage
Start your coding agent in (or pointed at) the codebase you want to audit, then ask it to do a security audit:
security audit this codebase
find security vulnerabilities in ./src
do a security review, output to ~/audits/my-project
The skill activates automatically when the request matches its trigger (security audit, find vulnerabilities, pen-test the code, etc.). A direct codebase audit or pen-test request uses full audit mode. Security questions and focused vulnerability work use guidance mode unless you request report artifacts. In full audit mode, an unspecified output directory defaults to ~/security-audit-skill/<repo-name>/run-<N>. The workflow writes inside the target repository only when you explicitly select a directory that version control ignores.
Requirements
- A coding agent with a model that supports tool use and parallel sub-agents
- Node.js for the zero-dependency findings and coverage-ledger validators
- An OS-enforced sandbox for target-controlled builds, tests, processes, browsers, emulators, fuzzers, and fixtures. It must disable external networking, use a sanitized allowlisted environment, enforce resource limits, and allow writes only to assigned scratch paths. Without these controls, the workflow keeps the lead as
needs_validationinstead of executing target code.
Design principles
- Only confirm established boundary failures. Keep a source-grounded blocked lead as
needs_validationwith its exact unresolved fact. - Adversarial validation. The agent that checks a finding is never the agent that found it.
- Severity requires impact. Likelihood x impact, not deviation from a checklist.
- Defense-in-depth gaps are not vulnerabilities. If Layer A prevents the attack, the absence of Layer B is a hardening note.
- Multiple runs improve coverage. In our test runs, a single run found roughly half of the vulnerabilities that repeated runs found in total.
Contact
Questions, feedback, or comparing notes on AI-driven security tooling: security-ai-research@cloudflare.com
License
MIT -- see LICENSE.
Frequently Asked Questions
What is security-audit-skill?
security-audit-skill is an open-source ai agents skill for AI coding assistants such as Claude Code, Codex CLI, and ChatGPT, built by cloudflare. A coding-agent skill for multi-phase security audits with independently verified, machine-readable findings. It has 71,783 GitHub stars.
Is security-audit-skill safe to use?
security-audit-skill's catalog security scan is still queued. You can run an instant dependency and prompt-injection check now with the "Scan for vulnerabilities" button above.
How do I install security-audit-skill?
Clone the repository with "git clone https://github.com/cloudflare/security-audit-skill" and add it to your Claude Code skills directory (see the Installation section above).
What programming language is security-audit-skill written in?
security-audit-skill is primarily written in JavaScript. It is open-source under cloudflare on GitHub, so you can review or fork the full source.
Are there alternatives to security-audit-skill?
Yes. SkillsLLM lists many other AI Agents skills you can browse and compare side by side. Open the AI Agents category from the badge at the top of this page, or use the Related Skills and comparison links further down to weigh security-audit-skill against similar tools.
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