I'm having the same problem with my Scuf controller and its security screw. It is not, as others have claimed, external torx or "gamebit" as those are six spline drivers and this screw is pentalobe. It is basically an intverted/external pentalobe screw that would require a pentalobe socket of some kind. I'm still on the hunt because none of the proposed solutions would work except perhaps the security driver set listed by the last poster. However looking at the set he mentions I don't see a socket that would specifically fit this screw.
EDIT: I guess I'll gamble the under $20 for the bit set and see if it works.
EDIT 2: Nevermind, they charge as much for shipping as for the tool set, so that's not worth the gamble. I don't believe that tool set has the correct socket anyway. I've looked over the list of bits that it contains and I can rule out all of them except the two that are for opening cable boxes. It's possible that one of those might get the job done but I doubt it.