LAS VEGAS — In a city filled with slot machines spilling jackpots, it was a “jackpotted” ATM machine that got the most attention Wednesday at the Black Hat security conference, when researcher Barnaby Jack demonstrated two suave hacks against automated teller machines that allowed him to program them to spew out dozens of crisp bills. The demonstration was greeted with hoots and applause. In one of the attacks, Jack reprogrammed the ATM remotely over a network, without touching the machine; the second attack required he open the front panel and plug in a USB stick loaded with malware. Jack, a researcher with security firm IoActive, ...