Protecting web origins with Authenticated Origin Pulls
As we have been discussing this week, securing the connection between CloudFlare and the origin server is arguably just as important as securing the connection between end users and CloudFlare. The origin certificate authority we announced this week will help CloudFlare verify that it is talking to the correct origin server. But what about verification in the opposite direction? How can the origin verify that the client talking to it is actually CloudFlare?
TLS Client Authentication
TLS (the modern version of SSL) allows a client to verify the identity of the server it is talking to. Normally, a TLS handshake is one-way, that is, the client is able to verify the server's identity, but the server is not able to verify the client's identity. What about when both sides need to verify each other's identity?
Enter TLS Client Authentication. In a client authenticated TLS handshake both sides provide a certificate to be verified. If the origin server is configured to only accept requests which use a valid client certificate from CloudFlare, requests which have not passed through CloudFlare will be dropped (as they will not have our certificate). This means that attackers cannot circumvent CloudFlare features such as our WAF Continue reading