The black box takes control and issues dispense commands to the ATM, which is obeyed dutifully.
In general, Jackpotting refers to a category of attacks aiming to dispense cash from an ATM illegitimately.
Some incidents indicate that the black box contains individual parts of the software stack of the attacked ATM.
The investigation into how these parts were obtained by the fraudster is ongoing.
One possibility could be via an offline attack against an unencrypted hard disc.
source: www.techworm.net
