Do you know how many viruses and trojans there are named backdoor? Cant isolate which one, but a search of the mcaffe virus library for backdoor.sdb dosnet turn up anything.
With a name like backdoor, it probably does allow hackers (or more likely, script kiddies) into your computer, but only if you let it install itself.
You can look for more info here:
http://vil.nai.com/vil/default.asp
But as I said, backdoor is too common to be much good in a search.