Security Review

Systematic security checklist for code changes. Catch vulnerabilities before they ship.

When to Use

• After writing authentication or authorization code
• After handling user input (forms, query params, file uploads)
• After creating or modifying API endpoints
• After touching secrets, tokens, or credentials
• Before any commit that touches security-sensitive code

Procedure

Step 1: Identify Scope

Determine which checks apply based on changed files:

• Auth code: full checklist
• API endpoints: input validation, injection, rate limiting
• Frontend: XSS, CSRF
• Config/infra: secrets, permissions

Step 2: Run Checklist

Check	Severity	What to Look For
Hardcoded secrets	CRITICAL	API keys, passwords, tokens in source
SQL injection	CRITICAL	String concatenation in queries
Auth bypass	CRITICAL	Missing auth checks on protected routes
XSS	HIGH	Unsanitized user input in HTML output
CSRF	HIGH	Missing CSRF tokens on state-changing requests
Input validation	HIGH	Unvalidated user input passed to logic
Rate limiting	MEDIUM	Endpoints without rate limits
Error leaks	MEDIUM	Stack traces or internal details in responses
Authz checks	HIGH	Missing permission verification
Dependency vulns	MEDIUM	Known CVEs in dependencies

Step 3: Scan Code

# Check for hardcoded secrets (patterns)
grep -rn "password\s*=\s*['\"]" --include="*.{ts,js,py,go}" .
grep -rn "api_key\s*=\s*['\"]" --include="*.{ts,js,py,go}" .
grep -rn "secret\s*=\s*['\"]" --include="*.{ts,js,py,go}" .

# Check for SQL string concatenation
grep -rn "SELECT.*+.*FROM\|INSERT.*+.*INTO" --include="*.{ts,js,py,go}" .

# Check dependency audit
npm audit 2>/dev/null || pip-audit 2>/dev/null || true

Step 4: Report

Security Review: {scope description}

CRITICAL:
- {finding with file:line and fix}

HIGH:
- {finding with file:line and fix}

MEDIUM:
- {finding or "none"}

LOW:
- {finding or "none"}

Verdict: PASS | BLOCKED ({count} CRITICAL issues)

Blocking Rules

• CRITICAL: Must fix before commit. No exceptions.
• HIGH: Must fix before PR merge. Document if deferring.
• MEDIUM: Fix when possible. Track in backlog if deferring.
• LOW: Informational. Fix at convenience.

Output Format

Security Review: User authentication endpoints

CRITICAL: none
HIGH:
- src/api/login.ts:42 - Missing rate limiting on login endpoint
  Fix: Add express-rate-limit middleware (max 5 attempts/min)
MEDIUM:
- src/api/profile.ts:18 - Error response includes stack trace
  Fix: Use generic error message in production
LOW: none

Verdict: PASS (0 CRITICAL, 1 HIGH to fix before merge)

Rules

• Run on every commit that touches auth, input, or API code
• CRITICAL findings stop all work until fixed
• If secrets are found in code, rotate them immediately
• Never suppress findings; document accepted risks explicitly
• Check both new code AND existing code in modified files