Security Audit Skill

Degree of freedom: MIXED — Steps 0–4 judgment [HIGH freedom]; dependency and secret scans [LOW freedom — run exactly]. Never write exploit PoCs.

Audit-and-fix exception. May fix inline. Plan-only burndown → plan-security-audit. When fixing inline: patch the evidenced sink only, in place; unrelated weaknesses you notice go in the report as findings, not fixes. Add a test only where the repo already keeps security tests or the task asks. Auth behavior, RLS, secrets rotation, payments, and migrations stay STOP-and-confirm.

OWASP static review (injection, headers, deps). Session / route×gate / getSession() → audit-auth-flows. Next.js 16: grep middleware.ts and proxy.ts — a route gate can live in either file, and the proxy layer has its own bypass class.

This skill vs neighbors

How to reason

1. Observe — quote the sink or missing check (file:line)
2. Interpret — can untrusted input reach a query, HTML, or object-id?
3. Classify — injection / IDOR / secret / header / dep-CVE / hand-off
4. Severity — exploitable data access or hardcoded secret = Critical

Worked example

Observe: GET /documents/:id loads by id only (api/docs/route.ts:18). Interpret: any caller who can hit the route reads another user's doc. Classify: IDOR. Severity: Critical. Finding: IDOR | /documents/:id | add userId predicate. Matcher / getSession() on that route → audit-auth-flows, not this checklist.

Step 0: Understand the Project [HIGH freedom]

Before auditing, discover the tech stack and attack surface:

1. Read package.json / requirements.txt / go.mod to identify:

• Auth library (next-auth, passport, supabase-auth, django-auth, etc.)
• Database ORM (Prisma, Sequelize, SQLAlchemy, etc.)
• HTTP framework (Express, Fastify, Django, Flask, etc.)
• Any security-specific packages (helmet, cors, csurf, rate-limit, etc.)

1. Identify the auth pattern:

• Session-based vs JWT vs OAuth
• Where tokens are stored (cookies, localStorage, headers)
• How permissions/roles are enforced

1. Identify the data flow:

• Where user input enters the system
• How data is validated and sanitized
• How data reaches the database

Step 1: Research Current Threats [HIGH freedom]

Fetch current OWASP and security best practices for the detected stack:

firecrawl:firecrawl_search
{
 "query": "<framework> security best practices OWASP <current year>",
 "limit": 5,
 "sources": [{ "type": "web" }]
}

Scrape the OWASP Top 10 for the relevant platform:

firecrawl:firecrawl_scrape
{
 "url": "https://owasp.org/Top10/",
 "formats": ["markdown"],
 "onlyMainContent": true
}

Also check for known CVEs in dependencies:

firecrawl:firecrawl_search
{
 "query": "<package-name> CVE vulnerability <current year>",
 "limit": 5,
 "sources": [{ "type": "web" }]
}

Step 2: Check Production Security Errors (Sentry) [HIGH freedom]

If Sentry is configured, check for security-related production errors:

sentry:search_issues
{
 "organizationSlug": "<ORG_SLUG>",
 "query": "401 unauthorized OR 403 forbidden OR CORS OR CSP violation in last 30 days",
 "projectSlugOrId": "<PROJECT_SLUG>",
 "regionUrl": "<REGION_URL>",
 "limit": 20
}

Patterns that indicate security findings:

• Frequent 401/403 errors → possible auth bypass attempts
• CORS errors from unexpected origins → misconfigured CORS
• CSP violations → potential XSS vectors
• Rate limit errors → possible brute force

Step 3: Automated Code Scan [HIGH freedom]

Authentication Audit

• [ ] Passwords hashed with bcrypt/argon2/scrypt (not MD5/SHA1/SHA256 for passwords)
• [ ] Session tokens are cryptographically random
• [ ] Sessions expire appropriately (idle timeout + absolute timeout)
• [ ] Password reset tokens are single-use and expire quickly
• [ ] MFA available for sensitive accounts
• [ ] Login rate limiting implemented
• [ ] Account lockout after repeated failed attempts
• [ ] OAuth state parameter validated (CSRF protection for OAuth flows)
• [ ] JWT secret is strong and stored in env vars (not hardcoded)
• [ ] JWT expiry is reasonable (access: 15min, refresh: 7d)

Authorization Audit

• [ ] Every API endpoint checks permissions (not just authentication)
• [ ] No direct object references without ownership/permission check (IDOR)
• [ ] Role-based access properly enforced at the API layer (not just UI)
• [ ] Principle of least privilege followed
• [ ] Admin functions require elevated auth
• [ ] Row-Level Security (RLS) enabled for multi-tenant databases
• [ ] API keys scoped to minimum required permissions

Input Validation Audit

• [ ] All user input validated server-side (client validation is UX only)
• [ ] Input sanitized before use in queries, HTML, commands
• [ ] File uploads validated: type (MIME + magic bytes), size, filename
• [ ] JSON/XML parsing has depth/size limits
• [ ] URL parameters decoded and validated
• [ ] No raw SQL concatenation (parameterized queries only)
• [ ] No eval(), Function(), innerHTML with user input
• [ ] No dangerouslySetInnerHTML without DOMPurify

Data Protection Audit

• [ ] Sensitive data encrypted at rest
• [ ] TLS/HTTPS enforced (no HTTP fallback)
• [ ] Secrets not in code, git history, or logs
• [ ] PII handled according to applicable regulations (GDPR, CCPA)
• [ ] Database connections encrypted (SSL)
• [ ] API responses don't leak internal data (stack traces, SQL errors, file paths)
• [ ] Password fields use type="password" and autocomplete="new-password"

Security Headers Audit

• [ ] Strict-Transport-Security (HSTS) with long max-age
• [ ] Content-Security-Policy (CSP) configured (not just default-src *)
• [ ] X-Content-Type-Options: nosniff
• [ ] X-Frame-Options: DENY or SAMEORIGIN
• [ ] Referrer-Policy: strict-origin-when-cross-origin or stricter
• [ ] Permissions-Policy restricting unnecessary browser features
• [ ] CORS Access-Control-Allow-Origin is NOT * for authenticated endpoints
• [ ] Cookies: HttpOnly, Secure, SameSite=Strict (or Lax)

Dependency Audit [LOW freedom — run exactly]

npm audit # Node.js
pip-audit # Python
cargo audit # Rust
govulncheck ./... # Go
bundle audit # Ruby

• [ ] No known high/critical CVEs
• [ ] Dependencies reasonably up to date
• [ ] Lock file committed (package-lock.json, yarn.lock, pnpm-lock.yaml)
• [ ] No unnecessary dependencies (smaller surface area)

Step 4: Common Vulnerability Patterns [HIGH freedom]

Grep for the sinks, then read each hit in context:

• SQL injection — string interpolation into a query (` SELECT … ${ `, + userId +`); parameterized or ORM calls pass
• XSS — dangerouslySetInnerHTML / innerHTML fed user input without DOMPurify.sanitize
• IDOR — a load by req.params.id with no owner predicate (userId: req.user.id) on the query
• Sensitive data exposure — res.json(user)-style whole-record responses instead of an explicit field pick

Step 5: Environment and Secrets [LOW freedom — names/prefixes only]

Scan for Hardcoded Secrets

Search the codebase for potential leaked secrets. Patterns to look for:

• Generic secret names: api_key, apiKey, secret, password, token, credentials, private_key
• Key prefixes: sk-, pk-, ghp_, gho_, xox[bpsa]-, AKIA
• Private key headers: -----BEGIN (RSA|EC|OPENSSH) PRIVATE KEY-----

Verify .gitignore

.env, .env.local, .env.production
*.pem, *.key, *.p12
credentials.json, service-account.json
.sentryclirc (if it contains auth tokens)

Validate Environment Variables

import { z } from 'zod';

const envSchema = z.object({
 DATABASE_URL: z.string().url(),
 API_KEY: z.string().min(1),
 JWT_SECRET: z.string().min(32),
 SENTRY_DSN: z.string().url().optional(),
});

const env = envSchema.parse(process.env);

Self-critique before applying fixes [LOW freedom — do not skip]

1. Evidenced — file:line or audit output, not "this might be injectable"
2. Reproducible — same sink still present; no exploit PoC written
3. Severity justified — Critical = demonstrated data access or leaked secret
4. Right owner — session/route×gate/getSession → audit-auth-flows; RLS → plan-rls-audit; LLM → audit-llm-security
5. No-false-safety — headers or middleware alone ≠ authorization

Output: Security Audit Report

## Security Audit: [Project Name]

### Tech Stack
- Framework: [name + version]
- Auth: [library + pattern]
- Database: [ORM + provider]
- Security packages: [list]

### Critical Issues (must fix)
| # | Category | Finding | File | Recommendation |
|---|----------|---------|------|----------------|
| 1 | Auth | JWT secret hardcoded | config.ts:12 | Move to env var |

### High Risk (should fix soon)
| # | Category | Finding | File | Recommendation |
|---|----------|---------|------|----------------|

### Medium Risk (improve when possible)
| # | Category | Finding | File | Recommendation |
|---|----------|---------|------|----------------|

### Passed Checks
- [list of security areas that are properly implemented]

### Dependencies
- Critical CVEs: [count] — [details]
- High CVEs: [count]
- Outdated packages: [count]

### Research Sources
- [URL] — [what it confirmed or revealed]

Session / route×gate / getSession() findings belong on audit-auth-flows, not in this OWASP checklist.