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Webhook Security

Comprehensive guide to securing your webhook integrations against common threats and vulnerabilities.

Signature Verification​

Why Verify Signatures​

Webhook signatures ensure:

  • Authenticity - Request came from the expected source
  • Integrity - Data hasn't been tampered with
  • Non-repudiation - Source can't deny sending the webhook

Implementation Examples​

HMAC SHA-256 (Most Common)​

const crypto = require('crypto');

function verifyHMACSignature(payload, signature, secret) {
  const expectedSignature = crypto
    .createHmac('sha256', secret)
    .update(payload, 'utf8')
    .digest('hex');
    
  const receivedSignature = signature.replace('sha256=', '');
  
  return crypto.timingSafeEqual(
    Buffer.from(expectedSignature, 'hex'),
    Buffer.from(receivedSignature, 'hex')
  );
}

HTTPS and Transport Security​

TLS Configuration​

  • Use TLS 1.2 or higher
  • Strong cipher suites only
  • Valid SSL certificates
  • HSTS headers

Certificate Validation​

// Validate SSL certificates
const https = require('https');

const agent = new https.Agent({
  rejectUnauthorized: true, // Don't accept self-signed certificates
  checkServerIdentity: (host, cert) => {
    // Additional certificate validation
  }
});

Input Validation​

Sanitize All Input​

const Joi = require('joi');

const webhookSchema = Joi.object({
  id: Joi.string().required(),
  type: Joi.string().required(),
  data: Joi.object().required(),
  timestamp: Joi.number().integer().min(0)
});

app.post('/webhooks', (req, res) => {
  const { error } = webhookSchema.validate(req.body);
  if (error) {
    return res.status(400).json({ error: 'Invalid webhook data' });
  }
  
  // Process validated webhook
});

Rate Limiting and DDoS Protection​

Implement Rate Limiting​

const rateLimit = require('express-rate-limit');

const webhookLimiter = rateLimit({
  windowMs: 15 * 60 * 1000, // 15 minutes
  max: 1000, // Limit each IP to 1000 requests per windowMs
  message: 'Too many webhook requests'
});

app.use('/webhooks', webhookLimiter);

This section is under development. More security best practices coming soon.