Securing Webhooks

FusionAuth sends JSON events to your configured Webhooks that might include user information or other sensitive data. Therefore, it is important to ensure that your Webhooks are secured properly to prevent data from being leaked or stolen.

This document covers the standard methods for securing Webhooks. You can also learn more about verifying webhook message integrity.

TLS v1.2

The first step in securing your Webhooks is to ensure that they are using TLS v1.2 or higher. You should be using a web server that is configured with a certificate from a valid certificate authority and to only receive traffic from a secure connection. We also recommend that you disable all older secure protocols including SSL, TLS 1.0 and TLS 1.1.

If you need a certificate, most cloud providers offer them or you can use LetsEncrypt to generate a certificate and ensure it is always up-to-date.

Headers

When you configure your Webhook with FusionAuth, you should include a security header of some kind. There are two ways to define a security header:

Add a Basic Authentication username and password under Security
Define an HTTP header under the Headers tab

In either case, your Webhook code should validate the security header to ensure the request is coming from FusionAuth. Here’s some example code that validates an Authorization header:

Example Webhook


router.route('/fusionauth-webhook').post((req, res) => {
const authorization = req.header('Authorization');
if (authorization !== 'API-KEY') {
  res.status(401).send({
    'errors': [{
      'code': '[notAuthorized]'
    }]
  });
} else {
  // process the request 
}
});

Certificates

You may provide an X.509 certificate to use with your Webhook. This can be an SSL certificate previously added to Key Master or a manually entered SSL certificate in PEM format. It is used to establish a TLS connection to the Webhook endpoint. Use this option if FusionAuth cannot connect to your Webhook without the certificate.

Providing this certificate will build a custom SSL context for requests made for the Webhook. Therefore, any other JDK keystores and certificate authority chains will be bypassed for this request.

Firewalls

In addition to using TLS and a security header, you might also want to put a firewall in front of your Webhook. In most cases, this firewall will only allow traffic to your Webhook that originated from your FusionAuth instance. Depending on how you are hosting your Webhook, you might be able to lock down the URL for your Webhook specifically. You might also leverage an API gateway or a proxy to ensure that only traffic coming from FusionAuth is routed to your Webhook. The exact specifics of deploying and configuring a Firewall are outside the scope of this document, but you can consult the documentation for your proxy, API Gateway or hosting provider to determine how to manage it.

As an example, you can configure an AWS Application Load Balancer so that traffic coming from the IP address of your FusionAuth servers with a URL of https://apis.mycompany.com/fusionauth-webhook is routed through. You can then configure the Application Load Balancer so that all other traffic to that URL is rejected.

Controlling Traffic with a Proxy

Since version 1.31.0, FusionAuth can be configured to send all outbound HTTP traffic, including that from a Webhook, through a proxy. This allows you examine any messages sent from FusionAuth. You can audit them, only allow connections to certain hosts, or otherwise modify them.

To configure a proxy for FusionAuth outbound traffic, use the proxy.* configuration options.

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Securing Webhooks