SK Telecom warns customer USIM data exposed in malware attack

South Korea's largest mobile operator, SK Telecom, is warning that a malware infection allowed threat actors to access sensitive USIM-related information for customers. SK Telecom is the largest mobile network operator in South Korea, holding approximately 48.4% of the mobile phone service market in the country, corresponding to 34 million subscribers. The company says they detected malware on their systems at 11 PM local time on Saturday, April 19, 2025, in a weekend cyberattack when most organizations are understaffed. "Once we became aware of the possible leak, we immediately deleted the malware and isolated the equipment suspected of being hacked," reads the security notice. "As of now, there have been no confirmed cases of the leaked information being misused." The breach was reported to the Korea Internet & Security Agency (KISA) the following day, and the country's Personal Information Protection Commission was notified earlier today. Investigations are underway, and the c ... Read full article.