The hack does not require one to understand how the microprocessor or how the software behind the vulnerable device works. Johnston details the attack to the American public in a video his Assessment Team uploaded to Youtube. In order to make the rigged voting results look real the attack is based on vote swapping.
The video details how to replace a board from the voting machine with another one. The new board has a microprocessor that listens for remote activation of the “cheating mode”. While the modified board is in normal mode it behaves normally. But after someone activates the cheating mode vote swapping occurs. To make things even harder to detect the board is made in such a way that it lights up the light next to the person you thought you were voting.
For more details on how this device works check the Youtube video from the following link: http://www.youtube.com/watch?feature=player_embedded&v=6ClrHPShljM#