SK Telecom Hack Exposes 26 Million Mobile IDs

SK Telecom, South Korea’s largest wireless carrier, has disclosed a major cybersecurity breach involving a stealthy malware attack that persisted undetected for two years. The breach resulted in the unauthorized leakage of approximately 26 million International Mobile Subscriber Identity (IMSI) records—unique identifiers tied to mobile users and critical for network authentication and tracking.

The attack, uncovered recently, highlights the increasing sophistication of cyber threats targeting telecommunications infrastructure. While the specific vector of the malware has not been disclosed, the prolonged duration of the breach raises concerns about network monitoring capabilities and broader vulnerabilities within mobile operator systems.

SK Telecom has initiated internal investigations to assess the scope and impact of the compromise, while also taking steps to reinforce its cybersecurity defenses. The company has not yet confirmed whether customer data beyond IMSI records was affected. Regulatory authorities are expected to scrutinize the incident as part of broader efforts to safeguard national communications infrastructure.