Here is two rules for blocked some attack with the user-agent « Bittorrent »

Put it in the file modsecurity

SecRule REQUEST_HEADERS:User-Agent "Bittorrent" "id:10000002,rev:1,severity:2,log,msg:'Bittorrent Hit Detected'"

I would change the log to nolog after you verify it is working to avoid filling up your log file

SecRule REQUEST_HEADERS:User-Agent "Bittorrent" "id:10000002,rev:1,severity:2,nolog,msg:'Bittorrent Hit Detected'"

Put it in the config file apache


<IfModule mod_rewrite.c>
    RewriteEngine on
    # RewriteCond %{HTTP_USER_AGENT} =Bittorrent
    RewriteRule ^/announce$ - [F]
    RewriteRule ^/announce\.php$ - [F]
</IfModule>