Depending of if you have access and if it does not cause problems with any 'real' page names the following directive is quite helpful. There are plenty of thing that can be stopped by this but the last line worked prefectly for me.
<IfModule mod_rewrite.c>
RedirectMatch permanent (.*)cmd.exe(.*)$
http://www.microsoft.com
RedirectMatch permanent (.*)root.exe(.*)$
http://www.microsoft.com
RedirectMatch permanent (.*)\/_vti_bin\/(.*)$
http://www.microsoft.com
RedirectMatch permanent (.*)\/scripts\/\.\.(.*)$
http://www.microsoft.com
RedirectMatch permanent (.*)\/_mem_bin\/(.*)$
http://www.microsoft.com
RedirectMatch permanent (.*)\/msadc\/(.*)$
http://www.microsoft.com
RedirectMatch permanent (.*)\/MSADC\/(.*)$
http://www.microsoft.com
RedirectMatch permanent (.*)\/c\/winnt\/(.*)$
http://www.microsoft.com
RedirectMatch permanent (.*)\/d\/winnt\/(.*)$
http://www.microsoft.com
RedirectMatch permanent (.*)\/x90\/(.*)$
http://www.microsoft.com
</IfModule>