Coinone says hackers broke into its customer-support contractor and may have seen passwords, ID numbers and bank details that customers shared with support

South Korean crypto exchange Coinone said on Sunday that an attacker broke into servers run by its outsourced customer-support provider, MetaM, and that information customers handed over in support conversations may have been exposed.

According to crypto.news, the intrusion happened around 4 a.m. local time on November 12. Coinone learned of it at about 9:20 a.m. that day after MetaM reported it, and MetaM told the Korea Internet & Security Agency on November 13. Only customers who contacted Coinone's support center are affected, the exchange said.

What was exposed varies by customer. It could include names, phone numbers, email addresses, birth dates, bank account numbers, passwords, resident registration numbers, ID issue dates, home addresses, wallet addresses and transaction IDs. Coinone has not confirmed that every category was taken for every person, and it has not disclosed how many customers are involved.

The exchange says its trading, account and wallet systems run separately and that, as of Sunday, it had found no evidence of direct intrusion into them. It blocked the attacker's IP address, moved support to email and reported the incident to the internet security agency, the Personal Information Protection Commission and the Financial Supervisory Service. Customers who shared passwords with support are told to change them, and to watch for voice phishing that impersonates the exchange.