A hacker group calling itself Armada Collective has targeted three Greek banks and made bitcoin ransom demands.
The hackers were able to block internet activity of the banks. They could not, however, breach the banks’ security, confidential client information and client accounts.
The group initially undertook a distributed denial of service attack, overloading the banks’ websites with several requests.
Electronic transactions were also disrupted at all the three banks for a short period of time without revealing customer data.
One banker told Reuters, "All they achieved was to block the web banking for a few hours. Nothing else."
The banks declined to pay the ransom and informed the matter to the security services and the Greek central bank, which are undertaking an investigation.
The Armada Collective hackers group is carrying out cyber attacks to extort businesses In the recent years, the group threatened web service providers in Switzerland and banks in Thailand.
The group demands large sums of Bitcoin from the companies and threatens to carry out Distributed Denial of Service attacks.
