security-audit

name	security-audit
description	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.

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

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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

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Quick Scans (Run These First)

Secrets Scan

# 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

# Node.js
npm audit --json
# Python
pip audit
# Check for outdated
npm outdated

Security Headers Check

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

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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)

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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

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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.

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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