SK Telecom Malware Breach Affects 27 Million Customers Over Three Years

SK Telecom, South Korea's largest mobile network operator, reported a malware breach that lasted nearly three years, impacting approximately 26.95 million customers. The breach, detected on April 19, 2025, involved malware that compromised sensitive data, including IMSI and USIM authentication keys. An investigation revealed that the initial infection occurred on June 15, 2022, and 25 distinct malware types were identified across 23 servers. The company has since isolated the affected equipment and is notifying impacted customers. SK Telecom has pledged to take full responsibility for any damage caused and is enhancing its cybersecurity measures in response to this incident.

Key Points: • SK Telecom's malware breach lasted nearly three years, affecting 26.95 million customers. • The breach involved the compromise of sensitive data types, including IMSI and USIM keys. • SK Telecom is increasing its cybersecurity investments and restructuring its security governance.