Integrate fail2ban with CloudFlare

Following my previous post about using fail2ban to stop malicious requests to xmlrpc.php, I set up a CloudFlare account. In doing so, I ran into two issues:

First, my access logs were only showing CloudFlare’s IP address, not those of the users making the requests. That’s due to how CloudFlare proxies every request. Fortunately, CloudFlare provides an Apache module to translate the IP addresses for your logs.

Second, even with the correct IP address in the logs, fail2ban was no longer effective in stopping requests (since it handled the requests before the Apache module translated the IP addresses). I needed to stop the requests at CloudFlare, before they ever made it to my server. Fortunately, it’s simple to set up a fail2ban action that utilizes the CloudFlare API to block those requests. Create an action including:

actionban = curl -s "<ip>&u=<account>&tkn=<token>"
actionunban = curl -s "<ip>&u=<account>&tkn=<token>"

And set your filter(s) to use that action.

Stop Hack Attempts on WordPress xmlrpc.php

I recently noticed a lot of requests to this and other WordPress sites’ xmlrpc.php file. By “a lot”, I mean about 10-20 every second. It wasn’t particularly breaking anything (there aren’t any currently vulnerabilities there that I’m aware of), but it was increasing the load on my server.

My first step was to set an .htaccess rule to give a 403 response. That at least avoided hitting PHP with all those requests. But Apache still had to process them, so I wanted to take it a step further. I’m already using fail2ban, so I wanted to figure out how to stop these requests at that level instead of waiting until they reach Apache.
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