Earlier this year, SK Telecom faced a major cybersecurity breach that affected up to 26.9 million customers. The data breach, occurring in summer 2022, was revealed only this April after being reported to Korea Internet and Security Agency (KISA). The attack impacted 23 of SKT’s servers, resulting in the potential exfiltration of 9.32 gigabytes of USIM-related data. This included the exposure of 26.9 million International Mobile Subscriber Identity (IMSI) numbers.
SK Telecom promptly responded by offering free USIM card replacements to affected customers. However, the overwhelming demand led to a nationwide shortage of USIMs. Consequently, the government advised SKT to temporarily pause new subscriber acquisitions until the USIM stocks were replenished. For two months, SKT adhered to this guidance, focusing solely on resolving the shortage and securing necessary inventory.
In a recent development, the South Korean Ministry of Science and ICT announced the lifting of its administrative guidance. This allows SKT to resume acquiring new subscribers for their mobile services. The ministry confirmed that SKT now has sufficient USIM stock and a stabilized reservation system. However, they emphasized the importance of prioritizing the replacement of USIMs for affected customers.
“SK Telecom has secured sufficient USIM inventory to meet replacement demands and has successfully implemented and stabilized a new reservation system,” the ministry stated, thereby lifting the suspension on new subscriptions.
An official from SKT affirmed their readiness to onboard new customers while continuing support for those impacted by the cyberattack. “We are prepared to welcome new customers after successfully prioritizing USIM replacements for existing subscribers,” the official said, ensuring ongoing recovery efforts.
The ending of the subscription pause marks a significant recovery step for SKT. Despite this progress, the breach’s impact on the business is still unfolding. Many customers have switched to rival operators, with SKT’s CEO, Ryu Young-Sang, estimating a potential loss of up to 2.5 million customers. This could result in up to $5 billion in lost revenue over the next three years.
