Secure Your Application: 5 Things Every Developer Must Do
A comprehensive guide to implementing essential security measures in your applications, from authentication to data protection.
1. Implement Secure Authentication
Password Security
// Password hashing with bcrypt
const bcrypt = require('bcrypt');
async function hashPassword(password) {
const saltRounds = 12;
return await bcrypt.hash(password, saltRounds);
}
async function verifyPassword(password, hash) {
return await bcrypt.compare(password, hash);
}
JWT Implementation
// JWT token generation and verification
const jwt = require('jsonwebtoken');
function generateToken(user) {
return jwt.sign(
{ id: user.id, role: user.role },
process.env.JWT_SECRET,
{ expiresIn: '1h' }
);
}
function verifyToken(token) {
try {
return jwt.verify(token, process.env.JWT_SECRET);
} catch (error) {
throw new Error('Invalid token');
}
}
Multi-Factor Authentication
// MFA implementation
const speakeasy = require('speakeasy');
function generateMFASecret() {
return speakeasy.generateSecret({
name: 'YourApp:[email protected]'
});
}
function verifyMFAToken(secret, token) {
return speakeasy.totp.verify({
secret: secret,
encoding: 'base32',
token: token
});
}
2. Protect Against Common Vulnerabilities
SQL Injection Prevention
// Using parameterized queries
const { Pool } = require('pg');
const pool = new Pool();
async function getUser(email) {
const query = 'SELECT * FROM users WHERE email = $1';
const values = [email];
return await pool.query(query, values);
}
XSS Protection
// Input sanitization
const xss = require('xss');
function sanitizeInput(input) {
return xss(input, {
whiteList: {}, // No HTML allowed
stripIgnoreTag: true
});
}
// Content Security Policy
app.use(helmet.contentSecurityPolicy({
directives: {
defaultSrc: ["'self'"],
scriptSrc: ["'self'", "'unsafe-inline'"],
styleSrc: ["'self'", "'unsafe-inline'"],
imgSrc: ["'self'", "data:", "https:"],
connectSrc: ["'self'"]
}
}));
CSRF Protection
// CSRF token implementation
const csrf = require('csurf');
const csrfProtection = csrf({ cookie: true });
app.use(csrfProtection);
app.get('/form', csrfProtection, (req, res) => {
res.render('form', { csrfToken: req.csrfToken() });
});
3. Secure Data Transmission
HTTPS Implementation
// Express HTTPS setup
const https = require('https');
const fs = require('fs');
const options = {
key: fs.readFileSync('private.key'),
cert: fs.readFileSync('certificate.crt')
};
https.createServer(options, app).listen(443, () => {
console.log('HTTPS server running on port 443');
});
API Security
// Rate limiting
const rateLimit = require('express-rate-limit');
const limiter = rateLimit({
windowMs: 15 * 60 * 1000, // 15 minutes
max: 100 // limit each IP to 100 requests per windowMs
});
app.use('/api/', limiter);
// API key validation
function validateApiKey(req, res, next) {
const apiKey = req.headers['x-api-key'];
if (!apiKey || !isValidApiKey(apiKey)) {
return res.status(401).json({ error: 'Invalid API key' });
}
next();
}
4. Secure Data Storage
Encryption at Rest
// Data encryption
const crypto = require('crypto');
function encryptData(data, key) {
const iv = crypto.randomBytes(16);
const cipher = crypto.createCipheriv('aes-256-gcm', key, iv);
let encrypted = cipher.update(JSON.stringify(data), 'utf8', 'hex');
encrypted += cipher.final('hex');
const authTag = cipher.getAuthTag();
return {
iv: iv.toString('hex'),
encrypted,
authTag: authTag.toString('hex')
};
}
function decryptData(encryptedData, key) {
const decipher = crypto.createDecipheriv(
'aes-256-gcm',
key,
Buffer.from(encryptedData.iv, 'hex')
);
decipher.setAuthTag(Buffer.from(encryptedData.authTag, 'hex'));
let decrypted = decipher.update(encryptedData.encrypted, 'hex', 'utf8');
decrypted += decipher.final('utf8');
return JSON.parse(decrypted);
}
Secure File Storage
// Secure file upload
const multer = require('multer');
const path = require('path');
const storage = multer.diskStorage({
destination: (req, file, cb) => {
cb(null, 'uploads/');
},
filename: (req, file, cb) => {
const uniqueSuffix = Date.now() + '-' + Math.round(Math.random() * 1E9);
cb(null, file.fieldname + '-' + uniqueSuffix + path.extname(file.originalname));
}
});
const upload = multer({
storage: storage,
fileFilter: (req, file, cb) => {
const allowedTypes = ['image/jpeg', 'image/png', 'application/pdf'];
if (!allowedTypes.includes(file.mimetype)) {
cb(new Error('Invalid file type'), false);
return;
}
cb(null, true);
},
limits: {
fileSize: 5 * 1024 * 1024 // 5MB
}
});
5. Implement Security Monitoring
Logging
// Security logging
const winston = require('winston');
const logger = winston.createLogger({
level: 'info',
format: winston.format.json(),
transports: [
new winston.transports.File({ filename: 'error.log', level: 'error' }),
new winston.transports.File({ filename: 'combined.log' })
]
});
function logSecurityEvent(event) {
logger.info('Security Event', {
timestamp: new Date().toISOString(),
event: event.type,
user: event.user,
ip: event.ip,
details: event.details
});
}
Error Handling
// Secure error handling
app.use((err, req, res, next) => {
logger.error('Application Error', {
error: err.message,
stack: err.stack,
path: req.path,
method: req.method,
ip: req.ip
});
res.status(500).json({
error: 'An internal server error occurred'
});
});
Best Practices
1. Environment Variables
// Environment configuration
require('dotenv').config();
const config = {
jwtSecret: process.env.JWT_SECRET,
databaseUrl: process.env.DATABASE_URL,
apiKey: process.env.API_KEY
};
2. Security Headers
// Security headers middleware
const helmet = require('helmet');
app.use(helmet());
app.use(helmet.noSniff());
app.use(helmet.frameguard({ action: 'deny' }));
app.use(helmet.xssFilter());
3. Regular Security Audits
// Security audit logging
function auditSecurityEvent(event) {
const auditLog = {
timestamp: new Date().toISOString(),
event: event.type,
user: event.user,
action: event.action,
resource: event.resource,
status: event.status
};
// Store in secure audit log
storeAuditLog(auditLog);
}
Conclusion
This guide has covered:
- Secure authentication implementation
- Protection against common vulnerabilities
- Secure data transmission
- Secure data storage
- Security monitoring and logging
- Best practices for application security
Next Steps
- Review your current security measures
- Implement missing security features
- Set up security monitoring
- Conduct security testing
- Create security documentation
Resources
- OWASP Security Cheat Sheet
- Node.js Security Best Practices
- Express Security Best Practices
- JWT Security Best Practices
Citations
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