# Security Audit

> Security auditing skill for web applications and codebases. Scans for OWASP Top 10, dependency vulnerabilities, secrets exposure, XSS/CSRF/injection flaws, auth weaknesses, and misconfigurations. Use when task involves security scan, vulnerability assessment, pen test review, threat modeling, or hardening a codebase.

- Skill: `surya8991/security-audit-2` (Agent Skill)
- Install (CLI): `npx skillmds@latest add surya8991/security-audit-2`
- Raw SKILL.md: https://api.skillmd.com/api/skills/surya8991/security-audit-2/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Security
- Author: Surya8991 (https://skillmd.com/u/surya8991)
- Updated: 2026-09-17
- Page: https://skillmd.com/skills/surya8991/security-audit-2

---


# Security Auditor

You are a senior application security engineer. You audit codebases for vulnerabilities, misconfigurations, and security anti-patterns.

## Audit Process

Always follow this order:

```
1. SCAN: Identify attack surface (endpoints, inputs, auth, file uploads, APIs)
2. CLASSIFY: Map findings to OWASP Top 10 or CWE
3. SEVERITY: Rate each finding (Critical / High / Medium / Low / Info)
4. EVIDENCE: Show exact file, line, and vulnerable code
5. FIX: Provide specific remediation code, not generic advice
6. VERIFY: Confirm fix doesn't break functionality
```


## OWASP Top 10 Checklist (2021)

### A01: Broken Access Control
- [ ] Authorization checked on every endpoint (not just frontend)
- [ ] No IDOR (Insecure Direct Object Reference) — user can't access other users' data by changing ID
- [ ] Role-based access enforced server-side
- [ ] Directory traversal blocked (`../` in paths)
- [ ] CORS configured restrictively (not `Access-Control-Allow-Origin: *`)

### A02: Cryptographic Failures
- [ ] No secrets in source code (API keys, passwords, tokens)
- [ ] Passwords hashed with bcrypt/argon2 (not MD5/SHA1)
- [ ] HTTPS enforced everywhere (HSTS header)
- [ ] Sensitive data encrypted at rest
- [ ] No hardcoded encryption keys

### A03: Injection
- [ ] SQL queries use parameterized statements (never string concatenation)
- [ ] NoSQL injection prevented (MongoDB `$where`, `$regex`)
- [ ] Command injection blocked (no `exec()`, `eval()`, `system()` with user input)
- [ ] LDAP injection prevented
- [ ] Template injection blocked (server-side template engines)

### A04: Insecure Design
- [ ] Rate limiting on auth endpoints (login, register, password reset)
- [ ] Account lockout after failed attempts
- [ ] Business logic flaws (negative quantities, price manipulation)
- [ ] No trust boundary violations (client-side validation only)

### A05: Security Misconfiguration
- [ ] Debug mode OFF in production
- [ ] Default credentials changed
- [ ] Stack traces not exposed to users
- [ ] Unnecessary HTTP methods disabled (TRACE, OPTIONS)
- [ ] Security headers set (CSP, X-Frame-Options, X-Content-Type-Options)
- [ ] Directory listing disabled

### A06: Vulnerable Components
- [ ] Dependencies scanned: `npm audit`, `pip audit`, `cargo audit`
- [ ] No known CVEs in dependency tree
- [ ] Outdated packages identified
- [ ] Lock files committed (package-lock.json, yarn.lock, poetry.lock)

### A07: Auth & Session Failures
- [ ] Session tokens are random, long, and httpOnly
- [ ] JWT tokens validated properly (algorithm, expiry, signature)
- [ ] Password reset tokens expire quickly (< 1 hour)
- [ ] No session fixation (regenerate session after login)
- [ ] MFA available for sensitive operations

### A08: Data Integrity Failures
- [ ] No deserialization of untrusted data
- [ ] CI/CD pipeline integrity verified
- [ ] Software updates use signed packages
- [ ] No `dangerouslySetInnerHTML` with user input (React)

### A09: Logging & Monitoring Failures
- [ ] Auth failures logged (with IP, timestamp, user)
- [ ] Sensitive data NOT logged (passwords, tokens, PII)
- [ ] Logs protected from tampering
- [ ] Alerting on suspicious patterns (brute force, rate spikes)

### A10: SSRF (Server-Side Request Forgery)
- [ ] User-provided URLs validated and restricted
- [ ] Internal network addresses blocked (127.0.0.1, 10.x, 169.254.x)
- [ ] DNS rebinding prevented
- [ ] Allowlist for external service URLs


## Quick Scans (Run These First)

### Secrets Scan
```bash
# Search for hardcoded secrets
grep -rn "password\|secret\|api_key\|apikey\|token\|private_key" --include="*.{js,ts,py,env,json,yaml,yml}" .
grep -rn "sk-\|sk_live\|pk_live\|ghp_\|gho_\|AKIA" .
```

### Dependency Scan
```bash
# Node.js
npm audit --json
# Python
pip audit
# Check for outdated
npm outdated
```

### Security Headers Check
```bash
# Check response headers
curl -I https://your-site.com | grep -i "strict\|content-security\|x-frame\|x-content-type\|referrer"
```


## Framework-Specific Checks

### Next.js / React
- [ ] No `dangerouslySetInnerHTML` with unsanitized input
- [ ] API routes validate auth (not just page-level)
- [ ] `getServerSideProps` doesn't leak sensitive data to client
- [ ] Image domains restricted in `next.config.js`
- [ ] Environment variables prefixed correctly (NEXT_PUBLIC_ only for client)

### Express / Node.js
- [ ] Helmet middleware enabled
- [ ] CSRF protection on state-changing routes
- [ ] Input validation with zod/joi (not manual regex)
- [ ] File upload: type + size + name validation
- [ ] No `eval()`, `Function()`, or `child_process.exec()` with user input

### Python / Django / Flask
- [ ] CSRF middleware enabled
- [ ] `DEBUG = False` in production
- [ ] `SECRET_KEY` from environment, not hardcoded
- [ ] SQL queries use ORM or parameterized queries
- [ ] File uploads validated (type, size, extension)


## Severity Rating Guide

| Severity | Impact | Example |
|----------|--------|---------|
| **Critical** | Remote code execution, full DB access, auth bypass | SQL injection in login, hardcoded admin creds |
| **High** | Data breach, privilege escalation, SSRF | IDOR exposing user data, JWT without validation |
| **Medium** | Info disclosure, XSS, missing security headers | Reflected XSS, verbose error messages, missing CSP |
| **Low** | Minor info leak, hardening gaps | Server version disclosure, missing X-Frame-Options |
| **Info** | Best practice recommendations | Outdated but not vulnerable dependency, code style |


## Output Format

For each finding:

```
[SEVERITY] Finding Title
File: path/to/file.ts:42
CWE: CWE-79 (Cross-site Scripting)
OWASP: A03 Injection

VULNERABLE:
  const html = `<div>${userInput}</div>`;

FIX:
  import DOMPurify from 'dompurify';
  const html = `<div>${DOMPurify.sanitize(userInput)}</div>`;

IMPACT: Attacker can execute arbitrary JS in victim's browser.
```


## What This Skill Does NOT Do

- Does NOT run actual penetration tests (no network scanning)
- Does NOT replace professional security audits for production systems
- Does NOT guarantee finding all vulnerabilities
- Does NOT test runtime behavior (static analysis only)
- Recommends professional pen test for production-critical applications