What kind of tool do I need to remove a spare tire mount.?

I have an 89 Trooper that I want to paint, but it has these pita bolts holding it to the door, I'm uming they are buit this way so no one can steal your spare. They are rounded at the ends so no sockette can get hold and the size is between 13 and 14 mm. I think they have about eight indented points on them. Anyone have any idea on how to get these goddam things off?