Russian cryptocurrency exchange Livecoin posted on message on its official website on Christmas Eve claiming it was hacked and lost control of some of its servers, warning customers to stop using its services.
According to posts on social media, the attack seems to have happened on the night between December 23 and December 24.
Hackers appear to have taken control of the Livecoin infrastructure and then proceeded to modify the exchange rates to gigantic and unrealistic values.
Before Livecoin admins managed to gain back access to some of their systems during late December 24, the Bitcoin exchange rate had ballooned from the regular $23,000/BTC to more than $450,000/BTC, Ether grew from $600/ETH to $15,000, and Ripple price increased from $0.27/XRP to more than $17/XRP.
Once the exchange rates were modified, the mysterious attackers began cashing out accounts, generating gigantic profits.
In the message posted on its website, Livecoin admins described the incident as a "carefully planned attack, which has been prepared, as we assume, over the last few months."
"We lost control of all of our servers, backend and nodes. Thus, we were not able to stop our service in time. Our news channels were compromised as well," the company said.
"At the moment, we partially control frontend, and so we're able to place this announcement," it added.
While the main web-based exchange portal si down, Livecoin is now urging users to stop depositing funds and making transactions through other interfaces like the site's API and mobile apps.
As it happens with most cryptocurrency hacks, several users have cried foul play and are now claiming the entire hack was an inside job.
Livecoin said it notified local law enforcement.
According to CoinMarketCap, Livecoin is ranked as the 173rd cryptocurrency exchange on the internet, with roughly $16 million in daily transactions. The site has been active since March 2014.