The Banque Cantonale de Geneve (BCGE) is being held to ransom by a group of hackers claiming to have attacked company servers and downloaded 30,000 emails.
Rex Mundi, translated from Latin as "king of the world", announced the hack in a message posted to code repository DPaste. The post included leaked personal data said to have been taken in the attack as evidence that their threat was legitimate.
"We would like to mention that, as always, we did contact BCGE a few days ago and offered them not to post their data in exchange for a very reasonable amount of money," they said. "Since they declined our initial offer, we have therefore decided to post this initial leak."
They added that the full dump would be posted on their site hidden on the deep web, as well as on the publicly visible internet, on Friday 5pm GMT if the bank did not pay them €10,000 (£7,800).
Hélène De Vos Vuadens, a spokeswoman for the bank, told Swiss newspaper Le Temps that the attack had not reached the heart of the company’s systems, but merely the contact form on the bank’s site that handles basic queries.
"At worst, they have a user number," she said "But this is only one of the three bits of information that customers need to access their internet accounts."
She added that the banks contact forms had been considered sufficiently protected before the attack, and that the police had been informed of the situation.
Rex Mundi have a history of making good on their threats, having previously dumped data from AmeriCash loans after it refused to pay them an extortion fee as high as $20,000 (£13,200).
