Bithumb is one of the five largest bitcoin exchanges in the world. Hackers succeeded in grabbing the personal information of 31,800 Bithumb website users, including their names, mobile phone numbers and email addresses. The exchange claims that this number represents approximately three percent of customers. And the exchange further claims that the breach was made to a personal computer belonging to an employee, and not the exchange’s internal network, servers nor digital currency wallets. Attackers appear to have stolen enough credentials to begin a process of “voice phishing,” where the scammers call up victims one at a time and pose as representatives of Bithumb.