South Korean police have arrested two malicious hackers who compromised personal data of 8.7 million customers of KT Telecom, 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.
Hackers had stolen data such as customers' names, phone numbers and residential registration numbers and sold the information to telemarketing firms.
"It took nearly seven months to develop the hacking program and (the suspects) had very sophisticated hacking skills," a KT Corp. spokesperson told Yonhap News. "In light of this incident, we will strengthen the internal security system and raise awareness of security among all employees to prevent causing inconvenience to customers."
Seven other people were also booked for buying the leaked data for telemarketing purposes, Yonhap said.
The attack, described as one of the country's largest hacking schemes, is estimated to be valued at six figures: police said the two made about 1 billion won ($878,000).
"We deeply bow our head in apology for having your precious personal information leaked... we'll try our best to make such things never happen again," KT said in a statement to customers.
