On Wednesday, several NiceHash users reported that their BTC wallets had been emptied, which was later confirmed by NiceHash after its service went offline claiming to be undergoing maintenance.
At the time of writing, the NiceHash service is still offline with a post on its website, confirming that "there has been a security breach involving NiceHash website," and that hackers stole the contents of the NiceHash Bitcoin wallet.
Although NiceHash has not confirmed the number of bitcoins stolen from its virtual wallet, some of its customers have circulated a wallet address that suggests around 4,736 BTC—worth more than $70 million based on today's price—in total were drained from the company's wallet.
NiceHash has initiated an investigation into the matter, and has reported the incident to the "relevant authorities and law enforcement" and has been "co-operating with them as a matter of urgency."
The company also assured its customers that it is "fully committed to restoring the NiceHash service with the highest security measures at the earliest opportunity," but it's still unclear how the company will manage to settle everything if it is unable to compensate the total loss.
"We understand that you will have a lot of questions, and we ask for patience and understanding while we investigate the causes and find the appropriate solutions for the future of the service. We will endeavor to update you at regular intervals," the company says.Following the security incident, NiceHash is recommending its customers to change their passwords—both on NiceHash and other services, if they are using the same credentials.
NiceHash is the latest cryptocurrency company to suffer a significant blow in recent months. Another major hack took place last month due to a flaw in Parity's wallet that caused over $160 million in ETH (Ether) to be frozen, while nearly $32 million in ETH was stolen by hackers in July.