SK Telecom investigates data breach involving SIM-related information

SK Telecom (SKT), a major telecommunications operator in South Korea, confirmed on April 22, 2025, that it is investigating a data breach involving the unauthorized exposure of SIM-related information. The breach was detected late on the night of April 19, 2025, when malware was identified in the company’s systems.

In response, SKT promptly deleted the malicious code and isolated the suspected hacking device. While the company has not confirmed any misuse of the compromised data, it is conducting a thorough investigation to determine the exact cause, scale, and nature of the breach, including which specific personal data may have been leaked.

The company has reported the incident to the Korea Internet and Security Agency (KISA) and the Personal Information Protection Commission, in line with legal requirements. SKT is actively cooperating with authorities as part of the ongoing investigation.

To enhance customer protection, SK Telecom has implemented measures to block illegal SIM card changes and abnormal authentication attempts. Additionally, it has fortified its security systems to prevent similar incidents in the future.

For customers seeking additional security, SKT is offering a free SIM card protection service through its website and the T World portal. This service allows customers to receive notifications and take further steps to secure their accounts.