That widens Bitcoin's losses for the year to 50%.
Coinrail has confirmed that it suffered a "cyber intrusion" and while it did not specify the value of the coins stolen, local news outlet Yonhap News estimated it to be $37.28 million based on a loss of about 30 percent of the coins traded on the exchange.
Investors and regulators were jolted earlier this year after Japan's cryptocurrency exchange Coincheck was hacked in a high-profile theft of over half a billion dollars worth of digital currency.
The hack brought an abrupt end to two weeks of calm for the biggest virtual currency and reignited concerns about the security of lightly regulated crypto exchanges.
'Cyber intrusion': Bitcoin has biggest one-day fall in three months after hack
Bitcoin is now trading at $6,752 - down from an all-time peak of almost $20,000 in the week before Christmas.
Pundi X stated on its blog that the decentralized cryptocurrency exchange IDEX (where the stolen funds had been moved) agreed to urgently freeze the trading of NPXS coins on its platform, and all the stolen coins remain traceable for now.
Coinrail is not a member of the group that promotes self regulations to enhance security. It said it had frozen the tokens that were stolen and halted all trading across the exchange to help with a police investigation.
All assets of CoinRail, which have not been leaked, are moved to a cold wallet and are kept safe, and transactions and withdrawals will resume after stabilizing the service.
Korea Internet & Security Agency, now carrying out the investigation with police, said only four of the country's largest exchanges are subject to the Information Security Management System certification (ISMS) requirement. The company wasn't immediately available for further comments.
Cyberpunk 2077 Trailer Revealed At E3 2018
And we promise we'll do this before we start talking about pre-orders or ask anything of you. And, while this world is full of adrenaline, don't let the auto chases and guns mislead you.
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