I think it´s going to be difficult without creating a way to log loging attempts to a file. But if you want you can create a little hardening.
-
Rename the default installation folder (lists) and change the location of the admin folder. Remember to edit the config.php
$pageroot = '/lists'; $adminpages = '/lists/admin';
-
Add this lines to the admin .htaccess so only you can log in…
order allow,deny allow from xxx.xx.xxxx deny from all