Malware targeting Wincor Nixdorf cash machines takes $2.2m from Taiwanese bank's cash machines in one weekend

Surveillance videos show the machines churning out cash - with no apparent tampering

Banks across Taiwan have stopped dispensing cash from Wincor Nixdorf ATMs following a string of thefts in which one bank reportedly lost more than $2.2m over the last weekend. The bank suspects thieves used a specialist form of malware is responsible for the heists - but doesn't yet know how they infiltrated the cash machines.

The bank affected, First Bank, saw 34 ATMs at 20 branches in Taipei, New Taipei and Taichung drained of cash by the thieves. Surveillance videos released earlier this week by Taiwanese police implicate three suspects, who police say arrived in the country on Friday and left the country on Monday.

The surveillance videos show that the thieves were able to conduct the thefts without inserting cards or apparently tampering with the ATMs in any "improper or illegal way", according to the bank. The videos show the machines simply churning out all the New Taiwanese dollars they were holding, which was scooped up by the thieves before they moved on to their next target.

The country's biggest eight banks, including Bank of Taiwan and Chang Hwa Bank, as well as First Bank, have suspended services while their estates of Wincor Nixdorf cash machines are checked for signs of tampering and malware.

It's not clear whether the thieves laundered the money before fleeing Taiwan, had accomplices who helped them launder the cash locally, or used informal channels to convert the cash and/or send it abroad before they left. Interpol has been alerted in a bid to track down the suspects. Local reports have suggested that at least two of the three suspects were Russian nationals.

First Bank will be forced to bear all the losses from the series of thefts by the regulator, the Financial Supervisory Commission. The regulator has also ordered First Bank to provide a full and public explanation and to conduct an urgent review into its internal controls to avoid similar incidents in the future.