South Korea’s Ministry of Science and ICT (MSIT) set up a public-private team to investigate unauthorised mobile payments impacting KT customers, with the damage estimated at KRW45.8 million ($33,000), Yonhap News Agency reported.

KT disclosed the breach to the Korea Internet and Security Agency (KISA) on Monday (8 September) and said it found no signs of personal information hacking.

The operator added it then blocked any unusual payment requests, while confirming no additional breaches had taken place, the news service stated.

Hackers are suspected of using an illegal micro base station, or femtocell, to collect user data, Chosun Business reported.

The probe will be led by an advisory group of experts from MSIT, KISA and the private sector.

The operator said it is cooperating with investigations by police and the government.

KT is the second-largest mobile player in Korea, with 19.8 million subscribers at end-June, behind SK Telecom with 22.1 million.