Finally, our collective wish has been granted. There is a way to make cash machines spit out money and play music. And it’s done with stuff you can buy online. Barnaby Jack (yes, that is his real name) was another DefCon speaker on a crusade against security. He did pretty well.
Through a little complex coding know-how and a $100 hardware kit, Jack hacked into three different ATM machines. He said, "Every ATM I've looked at, I've found a 'game over' vulnerability that allowed me to get cash from the machine." With one of them, Jack physically broke in with a key he’d bought on the internet and managed to change the display and make it play a tune - while churning out money, of course. In another demo he broke in remotely using an internet phone link.
Video at link.