# South Korean corporate cybersecurity breaches

> Developing situation record from CLSTR: https://clstr.news/situations/south-korean-corporate-cybersecurity-breaches
> Updated: 2026-10-28T07:45:17.000Z. Sources: 13. Developments: 2.

South Korean authorities and private entities have responded to separate security incidents involving major domestic organizations. 

In late October, the Ministry of Science and ICT launched a joint investigation into Douzone Bizon, a provider of enterprise resource planning and groupware software. The company reported two breaches: one involving unauthorized access to internal development servers via a VPN, potentially exposing customer personal information, and another involving the exfiltration of encrypted data from a third-party backup server solution. 

Concurrently, the cryptocurrency exchange Bithumb reported a breach of its internal mobile groupware system, Daou Office. While Bithumb previously stated that core transaction infrastructure remained unaffected, new details confirmed that the unauthorized access, which occurred on October 27, lasted approximately one hour. 

The breach affected 715 employees or external contractors and 6,444 customer records. Although 5,600 customer records remained encrypted, personal information for 844 customers was confirmed to have been leaked. This exposed data may include names, mobile numbers, email addresses, resident registration numbers, bank account details, and copies of identification documents. 

Bithumb maintains that the compromised system is physically and operationally separate from its core trading platform and customer asset management systems, noting that no customer funds or wallet addresses were accessed. Regulators, including the Financial Services Commission and the Personal Information Protection Commission, have launched on-site inspections to investigate the cause and assess the extent of the exposure. Bithumb has pledged to compensate affected customers.

## Claims

- Bithumb's internal mobile groupware system, Daou Office, was breached by an external party. (reported by 7 sources)
- No customer cryptocurrency assets or wallet addresses were stolen. (reported by 5 sources)
- The compromised system is separate from the core cryptocurrency trading network. (reported by 4 sources)
- The breach affected 6,444 customer records and 715 employees or external staff. (reported by 3 sources)
- South Korean regulators have launched on-site inspections at Bithumb. (reported by 3 sources)
- Bithumb reported the breach to the Korea Internet & Security Agency and the Personal Information Protection Commission. (reported by 2 sources)

## Timeline

### 2026-10-28: Bithumb cryptocurrency exchange suffers data breach

South Korean crypto exchange Bithumb confirmed a breach of its internal groupware system, leaking data for 844 customers and 715 employees, though trading assets remain secure.

10 sources. https://clstr.news/cluster/bithumb-investigates-security-breach-involving-employee-data

### 2026-10-26: South Korean government launches investigation into Douzone Bizon security breaches

South Korean authorities have launched a joint investigation into Douzone Bizon following multiple security breaches that may have exposed sensitive client data and internal server information.

3 sources. https://clstr.news/cluster/south-korean-government-launches-investigation-into-douzone-bizon-security-breaches

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Cite as: South Korean corporate cybersecurity breaches. CLSTR, https://clstr.news/situations/south-korean-corporate-cybersecurity-breaches