SK Telecom USIM Information Hacking Incident Occurs

SK Telecom has experienced a security incident in which customer USIM-related information was leaked due to a hacking attack.

On the 22nd, SK Telecom issued an official apology through its customer center, stating, "We have detected suspicious circumstances indicating that some of your USIM-related information may have been leaked around 11:00 PM on April 19, 2025, due to malware."

According to SK Telecom, shortly after discovering signs of the leakage of some subscribers' USIM information at approximately 11:40 PM on the 19th due to a hacker's malware attack, the company immediately deleted the malware and isolated the suspected hacking equipment.

They have reported the incident to relevant organizations, including the Korea Internet & Security Agency (KISA), and are currently investigating the exact cause, scale, and items of the information leak.

Investigation of Damage Scale and Leaked Information Underway

A representative from SK Telecom stated, "The exact time of the attack is still under investigation," adding, "However, the leaked information consists of some USIM-related details such as the USIM key value, and personal information such as names, resident registration numbers, and addresses has not been leaked." Nevertheless, since the exact timing of the hacker's attack has not yet been identified, the possibility of an expanded scale of damage cannot be ruled out.

Personal Information Has Not Been Leaked

Currently, SK Telecom is conducting a thorough investigation into the scale and circumstances of the damage through digital forensics.

The leak of USIM information could lead to secondary damages such as USIM duplication, which requires users to remain vigilant.

Government Responds Immediately… Company Preparing to Implement 'Customer Protection Measures'

The Ministry of Science and ICT and KISA have also responded swiftly.

At 2:10 PM on the 21st, they requested the preservation and submission of materials related to the incident, and from 8 PM on the same day, KISA experts were dispatched to the site to provide technical support related to the investigation.

This incident has exposed vulnerabilities in the telecommunications provider's security, raising concerns about the potential for the misuse of telecommunication services and secondary damages resulting from the leaked USIM information.

SK Telecom is expected to formulate customer protection measures based on the results of the additional investigation.

Image source: Photo=SK Telecom, Photo courtesy of SKT, Material photos for better understanding of the article / audext