As much as 400 million pesos (US $20.4 million) was stolen in April after hackers used hundreds of false orders to make transfers of hundreds of thousands of pesos to fake accounts in other banks.
The newspaper El Financiero today reported that unnamed sources said the money was quickly withdrawn through cash withdrawals from the phony accounts in what is now being called a cyber attack.
The sources also said hackers might had help from inside bank branches since such large cash withdrawals are uncommon.
A Bank of México official revealed Friday that there had been unauthorized transfers “in recent days” but would not call it a cyber attack nor would she provide information regarding the amount stolen.
El Financiero’s source said 150 million pesos was stolen from Banorte, the only bank so far to concede there had been an attack. The bank said no clients were affected.
BanBajío was cited as another victim, to the tune of 160 million pesos, although the bank today denied it had suffered a cyber attack on its system.
Lorena Martínez, head of the Bank of México’s payment system, said the bank’s SPEI interbank transfer system was not compromised.
Meanwhile, Mexico’s second largest bank has blamed hardware problems for what it called “intermittent” failures of its automatic teller machines and online banking services yesterday.
Many Citibanamex account holders were unable to withdraw cash from ATMs or make payments or conduct transfers online.
The bank said last night via Twitter that the service interruptions were caused by a hardware problem, and were not related to issues with inter-bank SPEI transfers.