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.
Bitcoin has dropped 11 percent since 5 p.m. After opening a probe into possible bitcoin price manipulation, the government agency is asking platforms like Coinbase, Kraken, itBit and Bitstamp to hand over relevant trading data from December of past year and on so authorities can see if manipulative bitcoin futures trading has had any effect on the price. Coinrail only said that it was cooperating with investigators and other exchanges to try and track down the perpetrators and recover the money.More news: 'The Band's Visit' and 'Harry Potter' win big at Tonys
The price of Bitcoin plunged 6.81 percent to trade at 7.5 million won ($6,987), the lowest since April 12, according to Bithumb, one of Korea's largest cryptocurrency exchanges.
"The markets are so thinly traded, primarily by retail accounts, that these guys can get really scared out of positions", he said. "70% of total coin and token reserves have been confirmed to be safely stored and moved to a cold wallet [not directly connected to the internet]".
Coinrail said the "cyber intrusion" it experienced on Sunday saw the theft of around 30 percent of coins traded on the exchange.More news: First ‘Bond girl’ Eunice Gayson dies aged 90
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.
In China, the Communist Party-run People's Daily reported on Friday that the country will continue to crack down on illegal fundraising and risks linked to Internet finance, quoting central bank officials. South Korea's Omnitel Inc. and Vidente Co. both retreated at least 4%, while Japan's Remixpoint Inc. slumped about 6%.More news: Trump doubles down on criticism of EU, Canada