Introduction
You may want to completely block access to autodiscover/autodiscover.xml and can be done so with some Apache directives.
Procedure
Modify /usr/local/apache/conf/includes/post_virtualhost_global.conf and add:
Alias /htdocs_autodiscover /usr/local/cpanel/htdocs/
ErrorDocument 404 /htdocs_autodiscover/404.shtml
RedirectMatch 404 ^.*[a|A]utodiscover.xml$
and then restart Apache with
/scripts/restartsrv_httpd --hard