Police on Sunday arrested two hackers for stealing and selling on the personal information of 8.7 million KT users.
Investigators said they would also investigate KT on suspicion of negligent management of firewalls and personal data as the number of victims accounts for nearly half of its subscribers.
According to the National Police Agency, a telemarketing business operator and his coworker in February created a computer program that could penetrate KT’s firewalls. From then through July 15, the hackers harvested information related to mobile phone users and took advantage of the list in telemarketing activities, encouraging subscribers to switch to another mobile phone or pricing program.
The stolen information included the name, mobile phone number, membership number, personal identification number and mobile phone serial number of each subscriber.
The suspects also reportedly sold the information and the program to other telemarketers.
Seven people reportedly paid 2-3 million won ($1,785) a month for the hacking program, using it to pilfer the personal information of 2 million subscribers between April and July 15. The buyers were booked without detention.
The telemarketing firm operator reportedly inserted malware into the hacking software he supplied them to get hold of information that his buyers gathered on their computer hard drives.
He is reported to have raked in more than 1 billion won ($890,000).
“(The operator) disguised himself as a local KT branch manager when accessing the database and took the information gradually rather than conduct a simultaneous and large-scale hacking. Had he conducted some mass leak, he would have been caught a long time ago,” an NPA officer said. The police confiscated the telemarketing operator’s computers and all information he stored.
Investigators have also asked the other telecommunications companies, LG and SKT, to check their databases. Officers said they would study KT’s liability.
This is the sixth time in five years a large company has been reported a huge data leak. A total of 10 million people’s private information was leaked when www.auction.co.kr was hacked in 2009, followed by GS Caltex’s 11 million in 2010, Cyworld’s 35 million, Hyundai Capital’s 1.75 million and Nexon’s 13.2 million in 2011.
KT made a public apology on Sunday.
“After detecting the abnormality, the company on July 13 referred the case to the police. We have blocked all possible data leaks since then. We are sorry to have burdened our customers with concerns,” it said in a press release.
Those who would like to check whether their information has been leaked should visit the KT website, www.olleh.com, or call 1588-0010.