In yet another Bitcoin exchange hacking, South Korean cryptocurrency platform Youbit on Tuesday filed for bankruptcy, saying it is shutting down operations after being hacked for the second time in less than eight months.

The hack caused the cryptocurrency exchange loss worth 17 per cent of its total assets. However, Youbit did not disclose the amount, BBC reported.

“All customers’ cryptocurrency assets would be marked down to 75 per cent of their value,” Youbit was quoted as saying by The Guardian.

Youbit said it has stopped trading and would work to minimise customer losses.

Formerly known as Yapizon, the digital currency exchange lost 4,000 bitcoins (worth $73 million) to cyber thieves in an attack in April this year. The country’s spy agency had linked the cyber attack to North Korea.

The fresh Bitcoin hacking came after cryptocurrency mining market NiceHash revealed hackers wiped out its entire Bitcoin wallet, resulting in over $60 million loss.

NiceHash said its payment system was compromised and the contents of its Bitcoin wallet were stolen. Coindesk reported that the loss is about 4,736.42 Bitcoins, worth more than $60 million.

Security researchers claim North Korea-based advanced persistent threat (APT) groups are increasingly attacking financial institutions and Bitcoin exchanges.

In a report in Sky News, independent security researcher Ashley Shen claimed that after executing cyber attacks to steal confidential data and intelligence, some of the APT groups are now attacking financial institutions including Bitcoin.

Earlier on Tuesday, one Bitcoin traded at around $18,800.