In what was earlier referred to as the Citibank ATM fraud, the sheer scale of this fraud is only now coming to light.

Banks scramble after cyber-breach | Chicago Tribune

Exact figures are unknown — some banks have reported numbers; others have not. It is thought that at least 350,000 accounts across the country were defrauded, involving more than $10 million in losses, according to some experts.
….
“In terms of financial damage, this is definitely the biggest documented case of debit-card fraud we know of,” said Avivah Litan, a banking analyst and online-fraud expert for Gartner Inc., an information-technology research company.
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Central Florida’s three major banks — Bank of America, Wachovia and SunTrust — have acknowledged notifying certain customers about the problem, closing an unspecified number of accounts and issuing new cards and PINs.

The frauds involve third party processors:

In one case alone, hackers invaded the
computers of an Atlanta-based credit-card-processing company, stealing
an estimated 40 million credit- and debit-card numbers. The company,
CardSystems Solutions Inc., processed card transactions for Visa,
MasterCard and all major card brands.

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