"Fallout from SKT Hacking: 400,000 Users Switch in Just One Month"

# SK Telecom Faces Subscriber Exodus and Surge in USIM Replacement Requests After Data Breach A significant subscriber exodus has hit South Korea’s telecom industry after SK Telecom announced a data breach, leading to nearly 400,000 subscribers leaving the provider within a month. The fallout has critically affected SK Telecom’s customer base as many switched to rival telecom providers KT and LG Uplus. Industry data from September 22 to October 21 shows that 395,517 subscribers left SK Telecom. Of these, 220,709 moved to KT, and 174,808 switched to LG Uplus. In contrast, only 43,567 subscribers joined SK Telecom during this period, resulting in a net loss of 351,950 subscribers for the company. # Data Breach Triggers Mass Migration The subscriber exodus began after SK Telecom publicly acknowledged the breach on September 22, disclosing that customer USIM (Universal Subscriber Identity Module) information had been hacked. The company first discovered the issue on September 19 and officially reported it to the Korea Internet & Security Agency (KISA) on September 20. Further escalating public concern, SK Telecom CEO Yoo Young-sang formally admitted the hacking incident in a statement on September 25, offering an apology and free USIM replacements to affected users. Despite these measures, subscriber departures accelerated following the announcement. Before the breach news, SK Telecom's average daily subscriber loss ranged between 2,000 and 4,000 users. From September 28 to October 2, the daily loss surged to approximately 35,000 subscribers. Although the pace has since slowed to around 10,000 daily departures, the churn rate remains higher than normal. # Over 3 Million USIM Cards Replaced Since the incident, 3.4 million SK Telecom customers—14% of its total subscriber base, including MVNO users—have replaced or reconfigured their USIM cards. By October 21, 3.23 million users had received new USIMs, and an additional 170,000 had reconfigured their cards. However, 5.67 million customers who applied for replacement USIMs are still in the queue. The surge in USIM replacement requests intensified after a second update from the Joint Investigation Team probing the breach. They revealed that three years ago, malicious code was embedded into customer authentication systems, interfacing with IMEI numbers (International Mobile Equipment Identity). Although both the team and SK Telecom assured the public that IMEI data had not leaked, consumer anxiety has driven USIM replacement requests to record highs. Daily USIM replacement requests skyrocketed from an average of 100,000 to a peak of 300,000, with October 21 setting a single-day record of 360,000 replacements. # SK Telecom Races to Address Backlogs Im Bong-ho, Head of the MNO Business Unit at SK Telecom, acknowledged the backlog and indicated that about 2.2 million customers, who have yet to receive guidance for USIM replacement or reconfiguration, would be contacted by next week. “Our goal is to ensure all reserved requests are processed by the end of this month,” he stated. He added that for those unable to complete replacements by then, additional guidance would be provided in early November. The company is also considering offering on-site replacement services for walk-in customers once demand stabilizes. SK Telecom plans to source an additional 5 million USIMs in November, followed by another 5 million in July, to meet future demand and maintain readiness. # Industry Challenges Amidst Security Concerns The breach underscores growing consumer concerns over data privacy and security in the telecom sector. Competitors KT and LG Uplus are gaining subscribers as customers flee from SK Telecom. How effectively SK Telecom manages its response to the crisis, including restoring public trust and resolving technical issues, will be crucial to maintaining its market position.