A recent cybersecurity breach involving unauthorized micro base stations has resulted in small-sum payment fraud targeting 278 KT Corp. subscribers, causing losses exceeding 170 million won ($122,400), according to the ICT ministry on Wednesday.
The Ministry of Science and ICT unveiled its interim findings during a briefing at the Seoul Government Complex, where Vice Minister Ryu Je-myung described the incident as “a grave cyber intrusion with direct financial damage to users.”
“In light of the monetary losses suffered by consumers, we have designated the incident as a major security breach,” Ryu said. “A joint investigation team comprising experts from both public and private sectors is currently conducting a thorough probe.”
Investigators discovered that the fraud originated from an illegally installed femtocell, a compact base station used to enhance mobile signal coverage. The unregistered device had managed to infiltrate KT’s mobile network, serving as a conduit for unauthorized transactions that impacted dozens of users.
In response, the ministry has requested other mobile carriers — SK Telecom and LG Uplus — to initiate internal network inspections and implement measures to block similar unauthorized devices. As of Wednesday, no such base stations have been detected on their networks.
“To proactively mitigate further threats, all three major telecom operators are now blocking new femtocell connections,” Ryu said. “Additionally, KT will share abnormal traffic patterns identified from the rogue base station with its peers to enhance cross-network surveillance.”
Authorities are now focusing on how the illicit base station was able to penetrate KT’s network, how the fraudulent mobile payments were processed and whether personal user data may have been compromised.
“We are also examining potential secondary attack vectors beyond the illegal base station itself,” the vice minister said.
The incident comes amid heightened concerns over national cybersecurity, following a cyberattack on SK Telecom, disclosed in April, that government officials believe may have involved state-sponsored actors.
According to the Gyeonggi Nambu Provincial Police, the fraud cases have primarily affected KT users residing in Gwangmyeong, Gyeonggi Province, and Geumcheon-gu, Seoul.
Since Aug. 27, victims have reported unauthorized mobile transactions involving gift certificates and public transit card payments — often totaling several hundred thousand won per case.
yeeun@heraldcorp.com
