Leading Italian lender UniCredit has admitted that information of as many as 400,000 of its customers in the country got exposed to hackers in a couple of cyber attacks in the past 10 months.

The large number of victims made it the most serious data breach suffered by an Italian lender. The first attack occurred in the months of September and October of last year and the second attack took place in June and July of this year.

A spokesperson for UniCredit claimed that no passwords were stolen during the hacking attacks, but personal as well as banking details of customers could have been accessed by the suspected hackers.

The spokesperson added that the suspected hackers carried out the attacks through an external commercial partner, whose identify wasn’t revealed.

The Italian lender, however, neither described how the hackers managed to access confidential data of thousands of its customers nor did it reveal when it became aware of the first intrusion.