LGU+ said on Tuesday it protected more than 30,000 customers who were at risk of voice phishing crimes last year.

LGU+ is tracking malicious app control servers operated by voice phishing and smishing criminal groups through its "customer damage prevention analysis system", an AI-based integrated analysis and response framework for internal and external data. It has been doing so since last year, and it said it is the only telecom operator in South Korea to do this.

Once a malicious app is installed on a smartphone, the criminal group can use the app control server to block all incoming calls to the phone. The group can also manipulate calls it makes so they appear as coming from police or prosecutors, and make the group answer the phone even if the victim reports it to police.

LGU+ said it traced and analysed about 800 malicious app control servers from February last year, when it began full operation of the tracking solution within the system, through the end of the year. It said it identified about 33,000 customers with traces of accessing servers due to malicious app installations and provided related information to police.

Police analysed the information provided by LGU+ and visited the homes of customers suspected to be victims to carry out protection and relief activities. Considering that the National Police Agency has identified the per-person loss for voice phishing victims in 2025 as about 53.84 million won, the preventive results for the roughly 33,000 customers with malicious app installations found by LGU+ amount to 1.8 trillion won when converted into a monetary value.

LGU+ is also operating additional safety measures to prevent voice phishing losses. It set up a system to immediately send alert messages via KakaoTalk if a customer's installation of a malicious app is confirmed.

Through alert messages sent over six months from late June last year, about 18,000 customers were able to recognise voice phishing crisis situations. Customers who received the alerts can get necessary help through police officers at nearby police stations or security specialist advisers stationed at about 1,800 LGU+ stores nationwide.

LGU+ also blocked about 220 million cases of access by malicious apps on its network last year. It said it blocked about 540 million spam text messages, a distribution channel for smishing URLs.

LGU+ said it will expand the use of AI technology this year across all areas, including responses to voice phishing, smishing and spam text messages. It will introduce and build new solutions to strengthen analysis of malicious URLs.