New York - Five people were arrested on Monday following a global "cyber heist" in which hackers stole $45m by overriding the cash withdrawal limits of prepaid debit cards, US officials said.
According to the US Justice Department, those arrested were said to be members of the New York cell of an "international cybercrime organisation, which used sophisticated intrusion techniques to hack into the systems of financial institutions, steal prepaid debit card data, and make fraudulent ATM withdrawals on a global scale."
Officials said the cyber-ring managed to steal $45m in late 2012 and early 2013 by manipulating the limits of prepaid debit cards from Abu Dhabi-based National Bank of Ras Al-Khaimah and Bank Muscat of Oman.
The five arrested individuals face charges unsealed in an indictment. Eight others were charged in May.
This type of heist is known in criminal circle as an "unlimited operation". Two were allegedly carried out: first on 22 December last year and again on 19 February and 20 February this year.
In the first heist, more than 4 500 ATM transactions were conducted in some 20 countries around the world, resulting in $5m in losses. In the second in February 2013, cybercells in 24 countries withdrew about $40m from ATMs, according to officials.
In the initial stage, taking several months, sophisticated hackers allegedly infiltrated credit card processors' computer networks, looking into databases of prepaid debit cards, a tool used often by employers and aid organisations.
Breaking into the system, the hackers eliminated withdrawal limits imposed by banks.
Next, the cybergang distributed the debit card numbers to its street associates called "cashers", who loaded more magnetic stripe cards, like gift cards, with the stolen data.
Those arrested on Monday were identified as Anthony Diaz, Saul Franjul, Saul Genao, Jaindhi Polanco and Jose Angeley Valerio.
"As alleged, just a few months ago, after exploiting cyber-weaknesses in the financial system to steal millions from ATMs, these defendants were packing bags to the brim with stolen cash, destined for the cybercriminal organisers of these attacks," said US Attorney Loretta Lynch.
"Today, we have sent them packing once again - but this time, to jail. We will not relent until all those responsible for these financially devastating cybercrimes are brought to justice."
Authorities said newly seized photographic evidence revealed that the defendants sent $800 000 of cash proceeds in luggage by bus for delivery to a cyberheist organiser.
A sixth defendant, Franklyn Ferreira, is a fugitive from justice.
Of those charged earlier this year, four have pleaded guilty to charges in the case.