security-review

Security Review Skill

This skill ensures all code follows security best practices and identifies potential vulnerabilities.

When to Activate

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

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

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

// ❌ 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)

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 } })
}

-- 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);

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 }} />
}

// 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()
  }
]

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
}

res.setHeader('Set-Cookie',
  session=${sessionId}; HttpOnly; Secure; SameSite=Strict)

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

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

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

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

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:

Resources

Remember: Security is not optional. One vulnerability can compromise the entire platform. When in doubt, err on the side of caution.