- SK Telecom confirmed to suffer from a malicious infection on a Saturday evening
- The attackers tried to steal USIM data
- The police and the government have been informed
SK Telecom, the largest telecommunications supplier in South Korea, recently undergone a malicious software infection, by which threat stakeholders have tried to enter USIM information from customers.
The attack took place in mid-April 2025, at night between Saturday and Sunday, while most of the employees were absent for the weekend.
The company’s computer team spotted the intrusion and quickly moved to isolate the affected termination points and prevent more data from being stolen. In the morning, SK Telecom informed the relevant authorities and started an investigation to determine exactly what happened and what was stolen.
Not affected github
So far, no data has appeared on the Dark Web and no one has taken responsibility for the attack.
An USIM (Identity Module of Universal Subscriber) is the successor of the old SIM card. It is used in 3G, 4G and 5G mobile networks and is in most devices with cellular connectivity.
Basically, an USIM authenticates the identity of the device on a network, stores subscriber data (international identity of mobile subscribers, authentication keys, contacts and sometimes SMS), encrypts information passing and allows secure access to mobile services such as calls, data or texts.
A cybercriminal could use the data to close the SIM card, follow the location of people, get around applications safety or listen to communications.
In other words, it was a rather dangerous attack. This is why the company has strengthened USIM Swaps blocks and abnormal authentication attempts. In addition, he said that he immediately suspend the service for accounts related to suspicious activity.
SK Telecom is the largest telecommunications supplier in South Korea, serving some 34 million subscribers (around 49% of the market). The rest is mainly divided between KT and LG U +.
It offers mobile services, Internet and IPTV, IP and Cloud services, IoT solutions, smart car technology and connected cars, quantum cryptography communication, etc. It was one of the world’s first companies to launch commercial 5G in 2019.
Via Bleeping Compompute
