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 organ...