loulanyue Security Review Skill
This skill ensures all code follows security best practices and identifies potential vulnerabilities.
When to Activate
- Implementing authentication or authorization
- Handling user input or file uploads
- Creating new API endpoints
- Working with secrets or credentials
- Implementing payment features
- Storing or transmitting sensitive data
- Integrating third-party APIs
Security Checklist
1. Secrets Management
❌ NEVER Do This
const apiKey = "sk-proj-xxxxx" // Hardcoded secret
const dbPassword = "password123" // In source code
✅ ALWAYS Do This
const apiKey = process.env.OPENAI_API_KEY
const dbUrl = process.env.DATABASE_URL
// Verify secrets exist
if (!apiKey) {
throw new Error('OPENAI_API_KEY not configured')
}
Verification Steps
- No hardcoded API keys, tokens, or passwords
- All secrets in environment variables
-
.env.localin .gitignore - No secrets in git history
- Production secrets in hosting platform (Vercel, Railway)
2. Input Validation
Always Validate User Input
import { z } from 'zod'
// Define validation schema
const CreateUserSchema = z.object({
email: z.string().email(),
name: z.string().min(1).max(100),
age: z.number().int().min(0).max(150)
})
// Validate before processing
export async function createUser(input: unknown) {
try {
const validated = CreateUserSchema.parse(input)
return await db.users.create(validated)
} catch (error) {
if (error instanceof z.ZodError) {
return { success: false, errors: error.errors }
}
throw error
}
}
File Upload Validation
function validateFileUpload(file: File) {
// Size check (5MB max)
const maxSize = 5 * 1024 * 1024
if (file.size > maxSize) {
throw new Error('File too large (max 5MB)')
}
// Type check
const allowedTypes = ['image/jpeg', 'image/png', 'image/gif']
if (!allowedTypes.includes(file.type)) {
throw new Error('Invalid file type')
}
// Extension check
const allowedExtensions = ['.jpg', '.jpeg', '.png', '.gif']
const extension = file.name.toLowerCase().match(/\.[^.]+$/)?.[0]
if (!extension || !allowedExtensions.includes(extension)) {
throw new Error('Invalid file extension')
}
return true
}
Verification Steps
- All user inputs validated with schemas
- File uploads restricted (size, type, extension)
- No direct use of user input in queries
- Whitelist validation (not blacklist)
- Error messages don't leak sensitive info
3. SQL Injection Prevention
❌ NEVER Concatenate SQL
// DANGEROUS - SQL Injection vulnerability
const query = `SELECT * FROM users WHERE email = '${userEmail}'`
await db.query(query)
✅ ALWAYS Use Parameterized Queries
// Safe - parameterized query
const { data } = await supabase
.from('users')
.select('*')
.eq('email', userEmail)
// Or with raw SQL
await db.query(
'SELECT * FROM users WHERE email = $1',
[userEmail]
)
Verification Steps
- All database queries use parameterized queries
- No string concatenation in SQL
- ORM/query builder used correctly
- Supabase queries properly sanitized
4. Authentication & Authorization
JWT Token Handling
// ❌ WRONG: localStorage (vulnerable to XSS)
localStorage.setItem('token', token)
// ✅ CORRECT: httpOnly cookies
res.setHeader('Set-Cookie',
`token=${token}; HttpOnly; Secure; SameSite=Strict; Max-Age=3600`)
Authorization Checks
export async function deleteUser(userId: string, requesterId: string) {
// ALWAYS verify authorization first
const requester = await db.users.findUnique({
where: { id: requesterId }
})
if (requester.role !== 'admin') {
return NextResponse.json(
{ error: 'Unauthorized' },
{ status: 403 }
)
}
// Proceed with deletion
await db.users.delete({ where: { id: userId } })
}
Row Level Security (Supabase)
-- Enable RLS on all tables
ALTER TABLE users ENABLE ROW LEVEL SECURITY;
-- Users can only view their own data
CREATE POLICY "Users view own data"
ON users FOR SELECT
USING (auth.uid() = id);
-- Users can only update their own data
CREATE POLICY "Users update own data"
ON users FOR UPDATE
USING (auth.uid() = id);
Verification Steps
- Tokens stored in httpOnly cookies (not localStorage)
- Authorization checks before sensitive operations
- Row Level Security enabled in Supabase
- Role-based access control implemented
- Session management secure
5. XSS Prevention
Sanitize HTML
import DOMPurify from 'isomorphic-dompurify'
// ALWAYS sanitize user-provided HTML
function renderUserContent(html: string) {
const clean = DOMPurify.sanitize(html, {
ALLOWED_TAGS: ['b', 'i', 'em', 'strong', 'p'],
ALLOWED_ATTR: []
})
return <div dangerouslySetInnerHTML={{ __html: clean }} />
}
Content Security Policy
// next.config.js
const securityHeaders = [
{
key: 'Content-Security-Policy',
value: `
default-src 'self';
script-src 'self' 'unsafe-eval' 'unsafe-inline';
style-src 'self' 'unsafe-inline';
img-src 'self' data: https:;
font-src 'self';
connect-src 'self' https://api.example.com;
`.replace(/\s{2,}/g, ' ').trim()
}
]
Verification Steps
- User-provided HTML sanitized
- CSP headers configured
- No unvalidated dynamic content rendering
- React's built-in XSS protection used
6. CSRF Protection
CSRF Tokens
import { csrf } from '@/lib/csrf'
export async function POST(request: Request) {
const token = request.headers.get('X-CSRF-Token')
if (!csrf.verify(token)) {
return NextResponse.json(
{ error: 'Invalid CSRF token' },
{ status: 403 }
)
}
// Process request
}
SameSite Cookies
res.setHeader('Set-Cookie',
`session=${sessionId}; HttpOnly; Secure; SameSite=Strict`)
Verification Steps
- CSRF tokens on state-changing operations
- SameSite=Strict on all cookies
- Double-submit cookie pattern implemented
7. Rate Limiting
API Rate Limiting
import rateLimit from 'express-rate-limit'
const limiter = rateLimit({
windowMs: 15 * 60 * 1000, // 15 minutes
max: 100, // 100 requests per window
message: 'Too many requests'
})
// Apply to routes
app.use('/api/', limiter)
Expensive Operations
// Aggressive rate limiting for searches
const searchLimiter = rateLimit({
windowMs: 60 * 1000, // 1 minute
max: 10, // 10 requests per minute
message: 'Too many search requests'
})
app.use('/api/search', searchLimiter)
Verification Steps
- Rate limiting on all API endpoints
- Stricter limits on expensive operations
- IP-based rate limiting
- User-based rate limiting (authenticated)
8. Sensitive Data Exposure
Logging
// ❌ WRONG: Logging sensitive data
console.log('User login:', { email, password })
console.log('Payment:', { cardNumber, cvv })
// ✅ CORRECT: Redact sensitive data
console.log('User login:', { email, userId })
console.log('Payment:', { last4: card.last4, userId })
Error Messages
// ❌ WRONG: Exposing internal details
catch (error) {
return NextResponse.json(
{ error: error.message, stack: error.stack },
{ status: 500 }
)
}
// ✅ CORRECT: Generic error messages
catch (error) {
console.error('Internal error:', error)
return NextResponse.json(
{ error: 'An error occurred. Please try again.' },
{ status: 500 }
)
}
Verification Steps
- No passwords, tokens, or secrets in logs
- Error messages generic for users
- Detailed errors only in server logs
- No stack traces exposed to users
9. Blockchain Security (Solana)
Wallet Verification
import { verify } from '@solana/web3.js'
async function verifyWalletOwnership(
publicKey: string,
signature: string,
message: string
) {
try {
const isValid = verify(
Buffer.from(message),
Buffer.from(signature, 'base64'),
Buffer.from(publicKey, 'base64')
)
return isValid
} catch (error) {
return false
}
}
Transaction Verification
async function verifyTransaction(transaction: Transaction) {
// Verify recipient
if (transaction.to !== expectedRecipient) {
throw new Error('Invalid recipient')
}
// Verify amount
if (transaction.amount > maxAmount) {
throw new Error('Amount exceeds limit')
}
// Verify user has sufficient balance
const balance = await getBalance(transaction.from)
if (balance < transaction.amount) {
throw new Error('Insufficient balance')
}
return true
}
Verification Steps
- Wallet signatures verified
- Transaction details validated
- Balance checks before transactions
- No blind transaction signing
10. Dependency Security
Regular Updates
# Check for vulnerabilities
npm audit
# Fix automatically fixable issues
npm audit fix
# Update dependencies
npm update
# Check for outdated packages
npm outdated
Lock Files
# ALWAYS commit lock files
git add package-lock.json
# Use in CI/CD for reproducible builds
npm ci # Instead of npm install
Verification Steps
- Dependencies up to date
- No known vulnerabilities (npm audit clean)
- Lock files committed
- Dependabot enabled on GitHub
- Regular security updates
Security Testing
Automated Security Tests
// Test authentication
test('requires authentication', async () => {
const response = await fetch('/api/protected')
expect(response.status).toBe(401)
})
// Test authorization
test('requires admin role', async () => {
const response = await fetch('/api/admin', {
headers: { Authorization: `Bearer ${userToken}` }
})
expect(response.status).toBe(403)
})
// Test input validation
test('rejects invalid input', async () => {
const response = await fetch('/api/users', {
method: 'POST',
body: JSON.stringify({ email: 'not-an-email' })
})
expect(response.status).toBe(400)
})
// Test rate limiting
test('enforces rate limits', async () => {
const requests = Array(101).fill(null).map(() =>
fetch('/api/endpoint')
)
const responses = await Promise.all(requests)
const tooManyRequests = responses.filter(r => r.status === 429)
expect(tooManyRequests.length).toBeGreaterThan(0)
})
Pre-Deployment Security Checklist
Before ANY production deployment:
- Secrets: No hardcoded secrets, all in env vars
- Input Validation: All user inputs validated
- SQL Injection: All queries parameterized
- XSS: User content sanitized
- CSRF: Protection enabled
- Authentication: Proper token handling
- Authorization: Role checks in place
- Rate Limiting: Enabled on all endpoints
- HTTPS: Enforced in production
- Security Headers: CSP, X-Frame-Options configured
- Error Handling: No sensitive data in errors
- Logging: No sensitive data logged
- Dependencies: Up to date, no vulnerabilities
- Row Level Security: Enabled in Supabase
- CORS: Properly configured
- File Uploads: Validated (size, type)
- Wallet Signatures: Verified (if blockchain)
Resources
Remember: Security is not optional. One vulnerability can compromise the entire platform. When in doubt, err on the side of caution.