Bithumb, Daishin and Mirae Asset report fresh cyberattacks as South Korea sends inspectors, with 38,490 Daishin customers' data leaked

Bithumb, Daishin Securities and Mirae Asset Global Investments each reported a cyber incident on Wednesday, adding to a run of attacks on South Korean financial firms. Bithumb said it found on Tuesday that someone had gained unauthorized access to its internal mobile groupware system for employees. A spokesperson told the Korea JoongAng Daily the system is not the core facility that handles crypto trading, and said no leak has been confirmed of data that could enable fraudulent transfers, such as wallet addresses. The Korea Times reports the data known to be exposed so far concerns employees, and that Bithumb is still checking whether customer information was affected.

Daishin said personal and credit information on 38,490 customers leaked after abnormal access to a server tied to an account-opening service, which the firm shares with an outside partner. Mirae Asset Global Investments says the systems involved serve employees, not individual clients, so customer information is not involved, though employee names, email addresses and files could be.

The Financial Services Commission held an emergency meeting, the Financial Supervisory Service started on-site inspections, and the National Police Agency opened a preliminary inquiry. Officials said about 4.4 million probing attempts detected on October 21 came from North Korean IP addresses, but stressed that this alone does not prove who is responsible. TechCrunch notes that researchers at CrowdStrike linked the September attacks to a suspected China-based hacker.

Correction, October 28, 2026: an earlier version said Mirae Asset reported that no sensitive personal information was leaked; the firm said customer information is not involved because the affected systems serve employees.