KT detects 20 illegal base stations behind unauthorized mobile payment breaches; 368 victims

KT Corp. said Friday it has detected 20 illegal micro base station identifications suspected of being used for unauthorized mobile payment breaches through its network, with 368 users suffering financial losses totaling 240 million won ($169,300).

The company said it conducted a comprehensive examination of all 150 million mobile payment transactions made between Aug. 1, 2024, and Sept. 10, 2025, including 8.4 million micropayments and 6.3 million direct carrier billing payments.

Micropayments refer to small-value digital purchases made through automated response systems or short message service, while DCB payments are transactions arranged directly by telecom operators.

It also analyzed 4.03 trillion cases of network access records during the cited period to identify log data from illegal micro base stations, also known as femtocells.

As a result, KT found 20 illegal femtocell IDs that had accessed its network, up from four in its initial report, with connection records involving about 22,200 users.

Among them, 368 users experienced actual financial damage, with unauthorized micropayments amounting to around 240 million won.

KT confirmed that there were no unauthorized payments made through DCB transactions and that no illegal payment attempts have been detected since Sept. 5, when the company blocked all suspicious micropayment activities.

"We have reported the results of the examination to relevant authorities, including the Personal Information Protection Commission," KT said. "We apologize for the delay in completing the review and will fully cooperate with the government and police in their ongoing investigation." (Yonhap)