Police are investigating the leak of personal information of 15 million customers of telecom providers SK Telecom, LG Uplus and KT. It would be the third massive leak of private data this year.
Last week, 12 million KT susbscribers' personal data was leaked after its website was hacked, and another massive leak in January exposed the personal information of more than 100 million customers of KB Kookmin, NH Nonghyup and Lotte Card.
Police on Monday said the personal information of 4.1 million customers were leaked, including names, mobile phone numbers, addresses and bank account numbers.
LG Uplus was the worst affected with 2.5 million customers, followed by SK Broadband with 1.5 million, KT with 60,000 and SK Telecom with 40,000. Police have summoned staff for questioning.
They fear that the data was sold to shady dealers in China and resold to a Korean criminal ring specializing in telephone fraud. Staffers who were questioned by police claimed the leak occurred at dealerships rather than headquarters, but police are also looking into possible hacking.