Around 1:30 pm local time, the company said, it noticed that some 4,503 BTC—worth about $308 million at the time—”illegally leaked” from its wallet. DMM has not yet given further explanation as to how the apparent hack was carried out, but said it was investigating the matter and had taken measures to prevent such an attack from happening again.
The company says that it will continue to guarantee all customer BTC deposits following the exploit. It has, however, suspended the buying of orders for spot trading, the opening of leveraged trading positions, and “screening of new account openings.”
Further, DMM has suspended processing of crypto withdrawals for the time being. Withdrawals of Japanese Yen are still permitted, but may take longer than usual. The hack marks the most substantial crypto-related exploit the industry has suffered in some time. No hack so far this year, or in 2023 for that matter, approached it in scale.
2022, however, saw a string of massive exploits directed at a mix of layer-1 blockchains, sidechains, crypto exchanges, and DeFi protocols. The largest hack that year, of the BNB Chain (formerly Binance Smart Chain), made away some $566 million worth of BNB.
Today’s crypto hack appears to be the second largest in Japan’s history. Back in 2018, hackers raided Coincheck, one of the country’s largest exchanges, for over $550 million worth of XEM, a peer-to-peer cryptocurrency.
