A European cyber criminal group has been reported as using USB drives infected with malware to steal money form ATMs and other cash machines.
The theft details were reported by two researchers at the annual Chaos Computing Congress, which was held in Hamburg, Germany.
According to the report, the criminals created holes in the machines to attach their infected drives and download the malware on them.
The criminals were reported as using a 12-digit code to activate the malware that would sequentially generate a separate interface allowing them to access machines' complete control.
The malware also enabled the thieves to repeatedly steal money form the machines without being detected as they used to cover the holes made.
The criminal gang is said to have profound knowledge of the target ATMs and had make their malware code hard to analyse.
Analysis of the malware mechanism showed distrust of the gang members as the person operating the machines had to get a second PIN code from the headquarters, based on numbers displayed on the ATM screen that changed everytime the malware was activated.