Security Best Practices for Web Applications

Web Application Security

Security is paramount in modern web applications. These best practices will help you protect your Next.js applications from common vulnerabilities.

Authentication & Authorization

Session Management

Implement secure session management:

// Use secure cookies
res.setHeader('Set-Cookie', 'auth-token=' + token + '; HttpOnly; Secure; SameSite=Strict');

Role-Based Access Control

function hasPermission(userRole, requiredRole) {
  const roleHierarchy = {
    admin: 3,
    editor: 2,
    user: 1
  };

  return roleHierarchy[userRole] >= roleHierarchy[requiredRole];
}

Input Validation

Validate all user inputs to prevent injection attacks:

import { z } from 'zod';

const postSchema = z.object({
  title: z.string().min(1).max(200),
  content: z.string().min(1),
  status: z.enum(['draft', 'published'])
});

const validatedData = postSchema.parse(input);

Security Headers

Implement security headers using middleware:

export function middleware(request) {
  const response = NextResponse.next();

  // Add security headers
  response.headers.set('X-Content-Type-Options', 'nosniff');
  response.headers.set('X-Frame-Options', 'DENY');
  response.headers.set('X-XSS-Protection', '1; mode=block');

  return response;
}