NiceHash paused operations for 24 hours following a devastating hack, and issued an official public statement on its website and through social media channels, urging users to change online passwords.
The company explained that it is still assessing the damage: "Our payment system was compromised and the contents of the NiceHash Bitcoin wallet have been stolen. We are working to verify the precise number of BTC taken." Some estimates have valued the loss to be worth millions of dollars.
Previously, NiceHash had tweeted about maintenance-related downtime, but hours later it tweeted that the issues were taking longer than expected, possibly after learning that a malicious third party had accessed its system.
MSN reported that the head of marketing for NiceHash called the hack, "a highly professional attack with sophisticated social engineering."
NiceHash has yet to respond to ETHNews for comment, but we will provide additional coverage as details emerge.