Security Review

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

FAIL: NEVER Do This

const apiKey = "sk-proj-xxxxx"  // Hardcoded secret
const dbPassword = "password123" // In source code

PASS: 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.local in .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

FAIL: NEVER Concatenate SQL

// DANGEROUS - SQL Injection vulnerability
const query = `SELECT * FROM users WHERE email = '${userEmail}'`
await db.query(query)

PASS: 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

// FAIL: WRONG: localStorage (vulnerable to XSS)
localStorage.setItem('token', token)

// PASS: 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

Start strict and loosen only with a documented removal plan. Do not default to 'unsafe-inline' or 'unsafe-eval'; they neutralize much of CSP's protection and should be treated as temporary compatibility debt.

// next.config.js
const securityHeaders = [
  {
    key: 'Content-Security-Policy',
    value: `
      default-src 'self';
      base-uri 'self';
      object-src 'none';
      frame-ancestors 'none';
      script-src 'self';
      style-src 'self';
      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

// FAIL: WRONG: Logging sensitive data
console.log('User login:', { email, password })
console.log('Payment:', { cardNumber, cvv })

// PASS: CORRECT: Redact sensitive data
console.log('User login:', { email, userId })
console.log('Payment:', { last4: card.last4, userId })

Error Messages

// FAIL: WRONG: Exposing internal details
catch (error) {
  return NextResponse.json(
    { error: error.message, stack: error.stack },
    { status: 500 }
  )
}

// PASS: 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

• OWASP Top 10
• Next.js Security
• Supabase Security
• Web Security Academy

---

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

Cloud & Infrastructure Security Skill

This skill ensures cloud infrastructure, CI/CD pipelines, and deployment configurations follow security best practices and comply with industry standards.

When to Activate

• Deploying applications to cloud platforms (AWS, Vercel, Railway, Cloudflare)
• Configuring IAM roles and permissions
• Setting up CI/CD pipelines
• Implementing infrastructure as code (Terraform, CloudFormation)
• Configuring logging and monitoring
• Managing secrets in cloud environments
• Setting up CDN and edge security
• Implementing disaster recovery and backup strategies

Cloud Security Checklist

1. IAM & Access Control

Principle of Least Privilege

# PASS: CORRECT: Minimal permissions
iam_role:
  permissions:
    - s3:GetObject  # Only read access
    - s3:ListBucket
  resources:
    - arn:aws:s3:::my-bucket/*  # Specific bucket only

# FAIL: WRONG: Overly broad permissions
iam_role:
  permissions:
    - s3:*  # All S3 actions
  resources:
    - "*"  # All resources

Multi-Factor Authentication (MFA)

# ALWAYS enable MFA for root/admin accounts
aws iam enable-mfa-device \
  --user-name admin \
  --serial-number arn:aws:iam::123456789:mfa/admin \
  --authentication-code1 123456 \
  --authentication-code2 789012

Verification Steps

• [ ] No root account usage in production
• [ ] MFA enabled for all privileged accounts
• [ ] Service accounts use roles, not long-lived credentials
• [ ] IAM policies follow least privilege
• [ ] Regular access reviews conducted
• [ ] Unused credentials rotated or removed

2. Secrets Management

Cloud Secrets Managers

// PASS: CORRECT: Use cloud secrets manager
import { SecretsManager } from '@aws-sdk/client-secrets-manager';

const client = new SecretsManager({ region: 'us-east-1' });
const secret = await client.getSecretValue({ SecretId: 'prod/api-key' });
const apiKey = JSON.parse(secret.SecretString).key;

// FAIL: WRONG: Hardcoded or in environment variables only
const apiKey = process.env.API_KEY; // Not rotated, not audited

Secrets Rotation

# Set up automatic rotation for database credentials
aws secretsmanager rotate-secret \
  --secret-id prod/db-password \
  --rotation-lambda-arn arn:aws:lambda:region:account:function:rotate \
  --rotation-rules AutomaticallyAfterDays=30

Verification Steps

• [ ] All secrets stored in cloud secrets manager (AWS Secrets Manager, Vercel Secrets)
• [ ] Automatic rotation enabled for database credentials
• [ ] API keys rotated at least quarterly
• [ ] No secrets in code, logs, or error messages
• [ ] Audit logging enabled for secret access

3. Network Security

VPC and Firewall Configuration

# PASS: CORRECT: Restricted security group
resource "aws_security_group" "app" {
  name = "app-sg"

  ingress {
    from_port   = 443
    to_port     = 443
    protocol    = "tcp"
    cidr_blocks = ["10.0.0.0/16"]  # Internal VPC only
  }

  egress {
    from_port   = 443
    to_port     = 443
    protocol    = "tcp"
    cidr_blocks = ["0.0.0.0/0"]  # Only HTTPS outbound
  }
}

# FAIL: WRONG: Open to the internet
resource "aws_security_group" "bad" {
  ingress {
    from_port   = 0
    to_port     = 65535
    protocol    = "tcp"
    cidr_blocks = ["0.0.0.0/0"]  # All ports, all IPs!
  }
}

Verification Steps

• [ ] Database not publicly accessible
• [ ] SSH/RDP ports restricted to VPN/bastion only
• [ ] Security groups follow least privilege
• [ ] Network ACLs configured
• [ ] VPC flow logs enabled

4. Logging & Monitoring

CloudWatch/Logging Configuration

// PASS: CORRECT: Comprehensive logging
import { CloudWatchLogsClient, CreateLogStreamCommand } from '@aws-sdk/client-cloudwatch-logs';

const logSecurityEvent = async (event: SecurityEvent) => {
  await cloudwatch.putLogEvents({
    logGroupName: '/aws/security/events',
    logStreamName: 'authentication',
    logEvents: [{
      timestamp: Date.now(),
      message: JSON.stringify({
        type: event.type,
        userId: event.userId,
        ip: event.ip,
        result: event.result,
        // Never log sensitive data
      })
    }]
  });
};

Verification Steps

• [ ] CloudWatch/logging enabled for all services
• [ ] Failed authentication attempts logged
• [ ] Admin actions audited
• [ ] Log retention configured (90+ days for compliance)
• [ ] Alerts configured for suspicious activity
• [ ] Logs centralized and tamper-proof

5. CI/CD Pipeline Security

Secure Pipeline Configuration

# PASS: CORRECT: Secure GitHub Actions workflow
name: Deploy

on:
  push:
    branches: [main]

jobs:
  deploy:
    runs-on: ubuntu-latest
    permissions:
      contents: read  # Minimal permissions

    steps:
      - uses: actions/checkout@v4

      # Scan for secrets
      - name: Secret scanning
        uses: trufflesecurity/trufflehog@main

      # Dependency audit
      - name: Audit dependencies
        run: npm audit --audit-level=high

      # Use OIDC, not long-lived tokens
      - name: Configure AWS credentials
        uses: aws-actions/configure-aws-credentials@v4
        with:
          role-to-assume: arn:aws:iam::123456789:role/GitHubActionsRole
          aws-region: us-east-1

Supply Chain Security

// package.json - Use lock files and integrity checks
{
  "scripts": {
    "install": "npm ci",  // Use ci for reproducible builds
    "audit": "npm audit --audit-level=moderate",
    "check": "npm outdated"
  }
}

Verification Steps

• [ ] OIDC used instead of long-lived credentials
• [ ] Secrets scanning in pipeline
• [ ] Dependency vulnerability scanning
• [ ] Container image scanning (if applicable)
• [ ] Branch protection rules enforced
• [ ] Code review required before merge
• [ ] Signed commits enforced

6. Cloudflare & CDN Security

Cloudflare Security Configuration

// PASS: CORRECT: Cloudflare Workers with security headers
export default {
  async fetch(request: Request): Promise<Response> {
    const response = await fetch(request);

    // Add security headers
    const headers = new Headers(response.headers);
    headers.set('X-Frame-Options', 'DENY');
    headers.set('X-Content-Type-Options', 'nosniff');
    headers.set('Referrer-Policy', 'strict-origin-when-cross-origin');
    headers.set('Permissions-Policy', 'geolocation=(), microphone=()');

    return new Response(response.body, {
      status: response.status,
      headers
    });
  }
};

WAF Rules

# Enable Cloudflare WAF managed rules
# - OWASP Core Ruleset
# - Cloudflare Managed Ruleset
# - Rate limiting rules
# - Bot protection

Verification Steps

• [ ] WAF enabled with OWASP rules
• [ ] Rate limiting configured
• [ ] Bot protection active
• [ ] DDoS protection enabled
• [ ] Security headers configured
• [ ] SSL/TLS strict mode enabled

7. Backup & Disaster Recovery

Automated Backups

# PASS: CORRECT: Automated RDS backups
resource "aws_db_instance" "main" {
  allocated_storage     = 20
  engine               = "postgres"

  backup_retention_period = 30  # 30 days retention
  backup_window          = "03:00-04:00"
  maintenance_window     = "mon:04:00-mon:05:00"

  enabled_cloudwatch_logs_exports = ["postgresql"]

  deletion_protection = true  # Prevent accidental deletion
}

Verification Steps

• [ ] Automated daily backups configured
• [ ] Backup retention meets compliance requirements
• [ ] Point-in-time recovery enabled
• [ ] Backup testing performed quarterly
• [ ] Disaster recovery plan documented
• [ ] RPO and RTO defined and tested

Pre-Deployment Cloud Security Checklist

Before ANY production cloud deployment:

• [ ] IAM: Root account not used, MFA enabled, least privilege policies
• [ ] Secrets: All secrets in cloud secrets manager with rotation
• [ ] Network: Security groups restricted, no public databases
• [ ] Logging: CloudWatch/logging enabled with retention
• [ ] Monitoring: Alerts configured for anomalies
• [ ] CI/CD: OIDC auth, secrets scanning, dependency audits
• [ ] CDN/WAF: Cloudflare WAF enabled with OWASP rules
• [ ] Encryption: Data encrypted at rest and in transit
• [ ] Backups: Automated backups with tested recovery
• [ ] Compliance: GDPR/HIPAA requirements met (if applicable)
• [ ] Documentation: Infrastructure documented, runbooks created
• [ ] Incident Response: Security incident plan in place

Common Cloud Security Misconfigurations

S3 Bucket Exposure

# FAIL: WRONG: Public bucket
aws s3api put-bucket-acl --bucket my-bucket --acl public-read

# PASS: CORRECT: Private bucket with specific access
aws s3api put-bucket-acl --bucket my-bucket --acl private
aws s3api put-bucket-policy --bucket my-bucket --policy file://policy.json

RDS Public Access

# FAIL: WRONG
resource "aws_db_instance" "bad" {
  publicly_accessible = true  # NEVER do this!
}

# PASS: CORRECT
resource "aws_db_instance" "good" {
  publicly_accessible = false
  vpc_security_group_ids = [aws_security_group.db.id]
}

Resources

• AWS Security Best Practices
• CIS AWS Foundations Benchmark
• Cloudflare Security Documentation
• OWASP Cloud Security
• Terraform Security Best Practices

Remember: Cloud misconfigurations are the leading cause of data breaches. A single exposed S3 bucket or overly permissive IAM policy can compromise your entire infrastructure. Always follow the principle of least privilege and defense in depth.