The gang managed to crack the encryption system used by the firm.
Each of these cards have a specified limit to the amount that can be withdrawn.
The inside link
The group had a internet of cashiers inside that bank that worked for them.
The huge number of cities were used most probably to deter and hoodwink the investigators.
The withdrawal of money from the accounts occurred in under 12 hours of the cracking of the code.
The hackers even tried destroying all trace of themselves on the web link to cover up their tracks.
He pleaded guilty of the crime in 2012.
Almost exactly one year later, the leaders of this attack were charged.
source: www.techworm.net