Bithumb says hackers breached internal employee system

Key points

• Bithumb found a breach of its internal employee system on Tuesday and notified regulators
• The exchange says the system is separate from trading, so customer crypto cannot be accessed
• Scope of any member data exposure is still being analyzed; no crypto losses reported
• Daishin Securities reported a leak affecting 38,490 customers; FSS is reviewing three firms

Bithumb, one of South Korea’s largest cryptocurrency exchanges, said an outside party broke into an internal system its employees use for work and messaging. The exchange discovered the intrusion on Tuesday and is still working out whether customer information was exposed, according to Korean media reports cited by CoinDesk and Cointelegraph.

What Bithumb has disclosed about the breach

The affected system is the in-house mobile platform that staff use to communicate internally. Bithumb reported the incident on the day it found it to the Korea Internet & Security Agency and the Personal Information Protection Commission, according to the reports, which relied on Yonhap News Agency.

Bithumb told Yonhap it was analyzing the exact scope of the incident, including whether member information was involved. CoinDesk reported that the company said personal information was taken, while Cointelegraph described the exchange as still determining whether member data leaked. Bithumb has not said how many people may be affected, and it has not said whether deposits or withdrawals were disrupted.

The exchange said the compromised work system runs separately from its virtual asset trading system. On that basis it said customer virtual assets cannot be accessed through this breach. CoinDesk reported that no loss of crypto funds had been reported as of Wednesday afternoon in Asia.

Other South Korean financial firms also hit

The incident came as South Korea’s Financial Supervisory Service (FSS) assessed cyberattacks at several firms. According to CoinDesk, the regulator was reviewing Bithumb, Daishin Securities and Mirae Asset Global Investments on Wednesday.

• Daishin Securities said personal and credit information for 38,490 customers was leaked in an outside attack.
• Mirae Asset Global Investments said it blocked abnormal access to some of its web systems and that investor information was not affected.

FSS Governor Lee Chan-jin told a meeting with bank holding company chairs that he understood major financial investment companies had experienced hacking incidents on Tuesday, CoinDesk reported. Earlier this month, Lee said cyberattacks had hit 16 South Korean financial firms as of Oct. 14, according to both outlets.

Why it adds to scrutiny of Bithumb’s controls

The breach follows an earlier operational error at the exchange. CoinDesk reported that in February Bithumb mistakenly credited customers with 620,000 bitcoin instead of 620,000 won, a sum it valued at more than $40 billion at the time. CoinDesk said CEO Lee Jae-won blamed weak internal controls for that episode and said the exchange was acutely aware of the deficiency in its internal system control.

Cointelegraph noted a separate report that Bithumb has set a 2028 IPO timetable while overhauling its internal controls. Neither outlet reported any finding on who carried out the latest attack or how the intruders gained access.

What to watch next

The open questions are the number of people whose data was involved, what types of information were taken, and whether regulators open a formal review of the exchange. Bithumb has not given a timeline for completing its analysis. The FSS assessment of the three firms is ongoing.

Because the incident involved an employee-facing system rather than the trading platform, the exchange says customer crypto holdings were not exposed. Any confirmation of leaked member data would still bring obligations under South Korean personal data rules, which the company has already begun to address by notifying the privacy regulator.