Bithumb Groupware Hack Exposes Data of 7,159 Users and Staff

South Korean crypto exchange Bithumb has confirmed that its internal groupware system was hacked, leaking the personal information of 7,159 people. According to the company, 6,444 of them are customers and 715 are employees.

Of the affected customers, the data of 844 people was exposed directly, while the information of the remaining 5,600 or so was taken in the form of encrypted files. The leaked customer data includes names, mobile phone numbers, email addresses, resident registration numbers, driver's license numbers, bank account numbers and copies of ID documents. The exact set of exposed items differs from customer to customer.

Timeline and response

The intrusion took place on October 27 between 11:28 a.m. and 12:27 p.m. Bithumb says it first noticed the abnormal access at 12:14 p.m. that day, while the attack was still under way.

Immediately afterwards, the company blocked the attacker's access route and completely suspended use of its mobile groupware. It is now running a security review and applying patches together with the developer of the service.

Bithumb plans to begin notifying affected customers individually, in sequence, from the afternoon of October 29.

Why it matters

The exposed items are among the most sensitive identifiers in South Korea. Combinations of resident registration numbers, ID copies and bank account details can be misused for identity fraud and phishing, so affected users have reason to stay alert to suspicious messages and calls.

Bithumb CEO Lee Jae-won apologized for the worry and anxiety caused to customers. He said the company will do its best to provide relief and compensation if secondary damage to affected users is confirmed.