The cryptocurrency markets tumbled sharply following the news, with Bitcoin dropping from $7,240 to $6,752 in less than two hours, with the current price being $6,794. While the latest hacking target - a South Korean venue called Coinrail - is much smaller, the news triggered knee-jerk selling by investors, according to Stephen Innes, head of Asia Pacific trading at Oanda Corp.in Singapore. The exchange said it has managed to freeze all exposed NPXS, NPER and ATX coins, and that other cryptocurrencies are now being kept in a cold wallet.
Bitcoin has dropped 11 percent since 5 p.m.
It notes that Bitcoin was trading at $6,790.88 on Bitstamp, a drop of 10.8 percent from Friday and a massive dip from its December 2017 peak, when it hit an all-time high of nearly $20,000.
The attack on Coinrail comes months after Japanese firm Coincheck said it had lost more than US$500 million in a January hack.
South Korean cryptocurrency exchange Coinrail was hacked on Sunday, losing about 30 percent of the coins traded there.
Enthusiasm for virtual currencies has waned partly due to a string of cyber heists, including the almost $500 million theft from Japanese exchange Coincheck Inc.in late January.
The largest cryptocurrency declined to US$6,840 as of 4pm in NY, the biggest drop since March 14, according to data compiled by Bloomberg from Bitstamp pricing.
The Korean National Police Agency is investigating the case, an official said by phone.
Coinrail did not specify the value of the currency that was taken in the attack at the weekend but said it was working with authorities and other coin developers to track down the culprits.
Some Asia-listed stocks with exposure to digital currencies fell on Monday.