Security researcher, Barnaby Jack, amazed attendees at the Black Hat security conference by hacking ATM machines by just using the internet. The two exploits are physical access to the ATM machine using a master key available online and the other dialing in remotely to gain access. Apparently Jack boasted that he can hacked into any ATM machines easily.
Jack said: This is the first time anyone has taken the approach of trying to attack the underlying software. It is time to find software defenses rather than hardware defenses. They have a flaw that lets me bypass all authentication on the device on the Internet, and I am the ATM at that stage.
Source: Hack attack hits ATM jackpots