A contractor handling customer consultation work for digital asset exchange Coinone was hacked, leaking customers' personal information. The leaked data may include information customers left during consultations, such as names, resident registration numbers and account numbers.

Coinone said in a notice on the 15th that an outside attacker illegally accessed the server of MetaM, a contractor handling its customer consultation work, and leaked customers' personal information.

The attacker is believed to have viewed and leaked customer consultation information stored on MetaM's server at around 4 a.m. on the 12th. Coinone became aware of the incident at 9:20 a.m. the same day.

Information that may have been leaked includes names, email addresses, phone numbers, dates of birth, account numbers, passwords, resident registration numbers, ID card issue dates, home addresses, wallet addresses and transaction IDs (TXID). The data covered information customers provided directly during consultations.

Coinone's member accounts and trading system, and its digital asset wallet system, are operated separately from the contractor's server. No signs of direct intrusion into Coinone's own systems have been confirmed so far.

Coinone blocked the internet address (IP) used in the attack and access to its customer center immediately after becoming aware of the incident. It switched customer center operations to email-based consultations.

It also strengthened security measures and reported the incident to the Korea Internet & Security Agency, the Personal Information Protection Commission and the Financial Supervisory Service. It is investigating the exact timing and circumstances of the leak with the contractor and specialised institutions.

A Coinone official said, "We are investigating the exact time and circumstances of the leak together with the contractor and specialised institutions." The official said, "Please watch out for secondary damage such as voice phishing that impersonates Coinone using the leaked information."