An anonymous reader writes "South Korea's second largest wireless service provider has apologized after personal data of 8.7 millions of its mobile phone subscribers was stolen by hackers. The details are suspected to have been sold to marketing firms, netting the hackers close to $1 million. From the article: 'South Korean police have arrested two men who allegedly stole the personal information of about 8.7 million cellphone customers from KT Corp., the second biggest mobile carrier in South Korea. The company alerted police on July 13 after detecting traces of hacking attacks. The data was collected for the last five months, starting in February 2012.'"