A series of bank hacker heists have hit more than 100 financial institutions, say Kaspersky researchers, and more than US$300 million appears to have walked as a result.
The attacks targeted employees at as-yet-unnamed banks with malware dubbed Carbanak that gave access to corporate networks, giving criminals access for more than two years.
The final figure could, however, be more than three times the number Kaspersky is willing to use at present, due to a series of $10 million transactions that are difficult to track.
Security bod Sergey Golovanov told The New York Times that the perps are fraudsters from Europe, China, and Russia.
"The goal was to mimic their (a bank's) activities," Golovanov said of research to be published today.
"That way, everything would look like a normal, everyday transaction."
Money was stolen in large amounts by temporarily inflating a customer's bank balance before wiring off the difference. This went under the radar of banks that verified account balances every 10 hours.
Attackers also used online banking and remote access to force ATMs to spit cash to waiting gang members.
One Kaspersky customer lost $10 million while another was fleeced $7.3 million through ATM withdrawals.
The attack, described as probably the "most sophisticated attack the world has seen", due to its very low profile, focussed on Russia banks, plus others in the United States, Europe, and Japan.
Industry groups and law enforcement agencies including Interpol and the Dutch National Police were investigating the attacks, the Times reported.
The attacks delivered the Carbanak malware through phishing emails sent and executed by bank staff. This appeared to grant a beach head from where criminals planted surveillance malware and remote access trojans and sought out employees charged with administering cash transfer and ATMs.
Criminals then established bank accounts in the US and China, reportedly with JP Morgan Chase and the Agricultural Bank of China, where large amounts of cash would be transferred up to four months after the initial breach. ®