Upon further review, I believe that Sir.Rhosis is correct: 12 point (triple square). Though, I've checked it out with a T40 and a torque bit driver (I didn't even know I had one. I owe you a beer for helping me find it
) 17 ft-lb isn't very much torque and a T40 will do in a pinch. However, perhaps it is more prudent to acquire the right bit for the job.