BTW, I've stumbled upon a 'bro_act.exe' for quite a time. Don't remember but it's not new. Perhaps some new variant or modified (i.e. by some script-kiddies/wannabes).

Since you said that it's not among AV Encyclopedia yet, making me a lil bit unsure of what AV your using. I'd recommend 1st. KAV, 2nd. AVG (not that good anyway) and 3rd. Avast. None other. Scrap Norton/McAfee/TrendMicro.

About mutated/modified variants, that's why you should get an AV capable of unpacking the files/runtimes (i.e. KAV). And capable of doing an immediate update of additional module (sometimes without even rebooting, i.e. KAV, AVG, plus their update is daily-basis). Most AV does only a plain signature detection, i.e. Norton, McAfee, TrendMicro (PCCillin). Their so-called Bloodhound (heuristics analysis) is a hoax.

Now I really feel that this should belong in the Technical Help Section