defense

Defense in Depth — Security Validation

Multi-layered security audit for web applications. Runs checks across 8 security layers.

Workflow

Run each layer sequentially. Report findings with severity (CRITICAL / HIGH / MEDIUM / LOW) and file:line references.

Layer 1: Secrets Scanning

Search for hardcoded secrets, API keys, tokens, and credentials.

grep -rn "API_KEY\|SECRET_KEY\|DATABASE_URL\|PRIVATE_KEY\|password\s*=\|sk_live\|sk_test" . \
  --include="*.ts" --include="*.tsx" --include="*.js" --include="*.py" --include="*.env" \
  | grep -v node_modules | grep -v ".next" | grep -v ".env.example" | grep -v __pycache__

Check:

• No secrets in source code (should be in .env only)
• .env is in .gitignore
• No secrets in git history: git log --all -p -S "sk_live\|API_KEY\|SECRET" -- . ':!.env*' | head -50

Layer 2: Authentication & Authorization

• Session handling: Token expiry, httpOnly/secure/sameSite cookies, invalidation on logout
• Route protection: Every API route checks auth before processing
• Role enforcement: Different user types can only access their own resources
• IDOR prevention: Resource access scoped by authenticated user

# Find potentially unprotected API routes
find . -path "*/api/*/route.ts" -o -path "*/api/*/route.js" | xargs grep -L "auth\|session\|token\|verify" 2>/dev/null

Layer 3: Input Validation

• All user inputs validated (schemas, type checks)
• No raw SQL — use parameterized queries / ORM only
• No command injection via string interpolation in shell calls
• File uploads have type/size restrictions
• URL parameters sanitized

# Check for template literal SQL or shell commands
grep -rn "exec(\`\|sql\`\|query(\`" . --include="*.ts" --include="*.js" | grep -v node_modules

Layer 4: Encryption

• At rest: Sensitive data encrypted in database
• In transit: HTTPS enforced, no HTTP fallbacks
• Key management: Keys in env vars, not source code, not logged

Layer 5: OWASP Top 10

#	Risk	What to Check
A01	Broken Access Control	Resource isolation, role checks, IDOR
A02	Cryptographic Failures	PII encryption, key management
A03	Injection	SQL, command, template injection
A04	Insecure Design	Business logic flaws
A05	Security Misconfiguration	Default creds, verbose errors, debug mode
A06	Vulnerable Components	npm audit, outdated dependencies
A07	Auth Failures	Session management, brute force protection
A08	Data Integrity	Webhook signatures, CSRF tokens
A09	Logging Failures	Audit trail, no PII in logs
A10	SSRF	URL validation on server-side requests

# Dependency vulnerabilities
npm audit --production 2>/dev/null | head -50

Layer 6: API Security

• Webhook signature verification (Stripe, etc.)
• API keys not exposed to client-side code
• Rate limiting on public endpoints
• CORS properly configured
• Content-Type validation

Layer 7: Rate Limiting & DoS Protection

• API routes have rate limiting
• Login endpoints have brute force protection
• File upload size limits enforced
• Expensive operations throttled

Layer 8: Sensitive Data Protection

• PII never logged
• PII not exposed in error messages
• Sensitive fields excluded from API responses
• Data retention policies enforced

# Check for PII in logs
grep -rn "console\.\(log\|error\|warn\).*\(password\|ssn\|social\|secret\|token\)" . \
  --include="*.ts" --include="*.js" | grep -v node_modules

Report Format

## Security Audit Report

### Critical Findings
- [CRITICAL] Description — file:line

### High Findings
- [HIGH] Description — file:line

### Medium/Low Findings
- [MEDIUM/LOW] Description — file:line

### Passed Checks
- [PASS] Layer description