Coinrail said it is cooperating with the police investigating the hack and said it will release an announcement with more details as soon as possible. However, South Korean news outlet Yonhap News - via The Guardian - reported that some 40 billion won worth of digital coins were grabbed by the hackers; that's some £27.8m in real-world money.
In January, bitcoin was forecast to reach $33,000 per coin by 2019, but after a tough start of the year for the world's most popular cryptocurrency, the estimate is now around $14,000.
Last November - before December's pricing peak - the amount of bitcoin held for investment was roughly three times that held by traders.
A cyberheist at a little-known virtual currency exchange helped wipe billions of dollars off the value of bitcoin and other digital currencies.
Cryptocurrencies are still popular, especially with young investors. "It is a minor player in the market and I can see how such small exchanges with lower standards on security level can be exposed to more risks", Kim Jin-Hwa, a representative at Korea Blockchain Industry Association. It was just one month ago that the currency had been touching $10,000.
It noted that all assets of Coinrail that have not been leaked have been shifted into a cold wallet, which are on devices not accessible through the internet.
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. "For the rest, we are looking into it with an investigative agency, related exchanges and coin developers", it said. "The company wasn't immediately available for further comments".