Hi,
This is not a hack at all!!!! Nor a virus, nothing his box is not even corrupted...
This (stupid) user; forward an external port to its STB webif...
Somebody find it and simply use the Send A Message option in the webif!
Try it on you own box, you will get the same screen.
It is very easy to find such opened OpenWebif, google is a friend to find them.
Want to play around yourself here are two example, just found by google search:
http://boosresidenz.no-ip.org/
Pr2