Three unnamed Greek banks are the most recent victims of an extortion campaign in which a hacker group is attempting to fully take down their websites. The group, calling itself the Armada Collective, apparently made its first demand on Thursday of last week, at which point it also launched the first of its distributed denial-of-service (DDoS) attacks. Those attacks succeeded in disrupting transactions at every bank, the Financial Times reported. DDoS attacks overload websites' servers in an effort to take them fully offline, and the Armada Collective has a set price to stop its efforts: each bank must pay 20,000 Bitcoin, or $7,208,200. The financial institutions aren’t bending under pressure, however, and are instead strengthening their DDoS defenses. Greece’s central bank and its police electronic crime unit are also monitoring the banks’ computer systems.

This same group attacked several email providers earlier this year along with blackmail attempts, according to FT. However, authorities said it remains unclear whether this most recent effort is truly the original group or just a copycat. DDoS extortion schemes are relatively common and easy to carry out, especially with the recent onslaught of automated tools that seamlessly coordinate attacks at a cheap price. At this point, DDoS attacks are more of an on-demand service than a thorough hack; everything's done with a push of a button. One DDoS-favoring group, Lizard Squad, put its own tool up for rental earlier this past year after successfully taking down Xbox Live and PlayStation Network.