XML-RPC is a protocol designed to diferents systems can interact in standarised way, but could be used to extract information from your wordpress.
Add to .htaccess root website folder
# WPCODETRICKS.COM - XMLRPC DISABLE with redirect
<IfModule mod_alias.c>
RedirectMatch 301 /(.*)/xmlrpc\.php$ # http://domain.tld/xmlrpc.php
RedirectMatch 301 /(.*)/wlwmanifest\.php$ # http://domain.tld/index.php
</IfModule>