Upbit, South Korea’s largest cryptocurrency exchange by transaction volume, has frozen digital user accounts as it found digital assets worth 58 billion won ($49.2 million) have disappeared, its operator Dunamu said on Nov. 27.

All cryptocurrencies in Upbit’s hot wallets -- digital wallets -- have been transferred to the cold storage -- or physical devices in its freeze, which will last for at least two weeks, Dunamu CEO Lee Sir-goo said in a letter. 

This came as, at around 1 p.m. Nov. 27, some 342,000 Ether -- a cryptocurrency generated on the Ethereum platform -- in a digital wallet of Upbit went to a wallet identified as “0xa09871AEadF4994Ca12f5c0b6056BBd1d343c029” in an abnormal transaction.

This marked the seventh-largest crypto exchange hack by volume, according to an estimate by Coindesk.

Dunamu said the asset loss will be reimbursed with Upbit’s own assets.

By Son Ji-hyoung (consnow@heraldcorp.com)