If you’re running Moveable Type please read up on how spammers are abusing mt-send-entry.cgi. The easiest way to fix this is to change the permissions to 000, which will disable the script. Or you can just delete it. It’s only used if you set up "mail this entry". You can test whether your change worked by going to http://www.example.com/MTDIR/mt-send-entry.cgi: if you get a 403 or 404 error you’ve fixed it.