api-security-hardening

# API Security Hardening Protect REST APIs against common vulnerabilities with multiple security layers. ## Security Middleware Stack (Express) ```javascript const helmet = require('helmet'); const rateLimit = require('express-rate-limit'); const mongoSanitize = require('express-mongo-sanitize'); const xss = require('xss-clean'); app.use(helmet()); app.use(mongoSanitize()); app.use(xss()); app.use('/api/', rateLimit({ windowMs: 15 * 60 * 1000, max: 100 })); app.use('/api/auth/', rateLimit({ windowMs: 15 * 60 * 1000, max: 5 })); ``` ## Input Validation ```javascript const { body, validationResult } = require('express-validator'); app.post('/users', body('email').isEmail().normalizeEmail(), body('password').isLength({ min: 8 }).matches(/[A-Z]/).matches(/[0-9]/), body('name').trim().escape().isLength({ max: 100 }), (req, res) => { const errors = validationResult(req); if (!errors.isEmpty()) { return res.status(400).json({ errors: errors.array() }); } // Process request } ); ``` ## Security Headers ```javascript app.use((req, res, next) => { res.setHeader('Content-Security-Policy', "default-src 'self'"); res.setHeader('X-Frame-Options', 'DENY'); res.setHeader('X-Content-Type-Options', 'nosniff'); res.setHeader('Strict-Transport-Security', 'max-age=31536000; includeSubDomains'); res.setHeader('X-XSS-Protection', '1; mode=block'); next(); }); ``` ## Security Checklist - [ ] HTTPS everywhere - [ ] Authentication on all...