This plugin will block all XML-RPC activity that doesn't originate from the Jetpack servers.
Love your Jetpack but under siege by XML-RPC attacks? This plugin will block all XML-RPC activity that doesn't originate from the Jetpack servers. Just install and activate the plugin and you're all set. There's no interface, no settings, it just works.
Just install and activate the plugin and you're all set. Pat yourself on the back.