Greece's central bank has been on alert following reports of cyberattacks against three Greek banks. Sources say hackers had demanded a ransom to be paid in the bitcoin electronic currency.
Greek police said Monday that a group calling itself Armada Collective had demanded units of the virtual currency bitcoin, redeemable for hundreds of thousands of euros, or else it would disrupt the banks' websites.
"It was a serious threat," an unnamed Bank of Greece official told the AFP news agency.
Officials from the unnamed banks said the institutions had refused to pay and instead alerted authorities. It's not unprecedented for hackers to make ransom demands with the threat of cyber attack.
Online banking disrupted
The hackers apparently made good on their threat and managed to crash the online banking services of the three banks on November 26 for several hours. Officials say no sensitive data or customer information was compromised.
"All they achieved was to block the web banking for a few hours. Nothing else," one unnamed banker told the Reuters news agency, speaking on condition of anonymity.
Central bank officials say a counter-operation by cybercrime police and the Greek intelligence agency restored the system within about an hour.
"We informed the police and the country's secret services are involved," a second banker told Reuters. "It's an easy to handle situation. There is no need for bank clients to worry."
A hacking extortion group using the same name was reported to have staged attacks against banks in Thailand in the past as well as several private email services earlier this month.
The attacks come as Greece's four main banks - National Bank, Piraeus Bank, Alpha Bank and Eurobank - are being recapitalized after suffering a deposit flight earlier this year, forcing the government to impose capital controls to keep the banks solvent.
jar/gsw (AFP, Reuters)
