SK Telecom has initiated a free USIM replacement program for its customers following a significant hacking incident that raised concerns about personal data security. As of April 28, 2025, customers flocked to stores nationwide, causing long lines and overwhelming demand for the replacement service.
The incident came to light on April 18, when SK Telecom confirmed that hackers had compromised its systems, leading to the leak of unique identification numbers associated with some customers' USIM cards. In response to the breach, CEO Yoo Young-sang publicly apologized on April 25, acknowledging the distress caused to customers and announcing measures to replace USIM cards free of charge for anyone who requested it.
Starting at 10 AM on April 28, the program rolled out across more than 2,600 T World stores and airport roaming centers. However, some devices, including certain kids' phones and smartwatches, were excluded from the replacement initiative. The company has secured approximately 1 million USIMs and plans to prepare an additional 5 million by the end of May, as they anticipate that about 25 million customers may need replacements.
As customers rushed to take advantage of the program, reports indicated that the online reservation system faced significant access issues, further complicating the situation. By the afternoon of April 28, the mobile application for T World displayed a waiting list of over 123,000 people for the USIM Protection Service, with estimated wait times approaching seven hours.
In light of the chaos surrounding the USIM replacements, SK Telecom has been recommending that customers also sign up for its USIM Protection Service, a free service introduced in 2023 aimed at preventing unauthorized access to telecommunications services, even if a USIM is cloned. Approximately 24% of SK Telecom's subscribers, or about 5.54 million people, are currently enrolled in this service.
Despite the company's efforts to promote the USIM Protection Service as a viable alternative to physical replacements, the overwhelming demand has led to frustration among customers. Many who visited stores on the first day of the replacement program left empty-handed due to a shortage of USIMs, prompting them to turn to the Protection Service instead.
SK Telecom emphasized that the USIM Protection Service is not only effective but also quicker and easier to use than going through the replacement process. However, the current situation has led to significant waiting times, causing dissatisfaction among users seeking immediate solutions to their security concerns.
The government has also taken notice of the incident, with Prime Minister Han Duck-soo instructing the Ministry of Science and ICT to conduct a thorough evaluation of the USIM Protection Service and the measures being implemented for replacements. Additionally, the National Intelligence Service and other relevant agencies have been directed to enhance cybersecurity protocols in response to the breach.
One alarming report surfaced on April 28, when a 60-year-old man from Busan claimed that he lost 50 million won from his bank account after his phone was hacked, highlighting the potential financial risks associated with the data breach. This incident has raised alarms about the need for proactive measures to prevent further damage, as many customers express concerns about the safety of their personal information and financial assets.
In response to the growing anxiety among users, SK Telecom has taken additional steps to bolster its security measures, including strengthening its Fraud Detection System (FDS) to prevent abnormal authentication attempts and expanding real-time monitoring capabilities.
For those looking to secure their USIMs against potential hacking, the most immediate action recommended is to enroll in the USIM Protection Service. This service effectively blocks any unauthorized use of a USIM on devices other than the one it is registered to, thus providing a layer of security against cloning attempts.
Signing up for the USIM Protection Service is straightforward and free for all SK Telecom customers. Users can register through the T World app or website by navigating to the additional services menu. Alternatively, customers can contact SK Telecom's customer service for assistance or visit a nearby store for help with the registration process.
However, customers should be aware that enrolling in the USIM Protection Service may restrict their roaming capabilities while traveling abroad. Those planning to travel are advised to temporarily cancel the service before their departure and re-enroll upon their return.
For individuals who have recently replaced their USIMs at their own expense between April 19 and 27, SK Telecom is offering retroactive reimbursement. Customers can bring their receipts to a local store to claim their refund, easing some of the financial burden caused by the hacking incident.
As the situation continues to evolve, it is crucial for customers to remain vigilant. If they suspect their USIM has been compromised, they should immediately check their enrollment in the USIM Protection Service and, if not already registered, sign up to prevent further damage. Changing the USIM PIN and monitoring bank accounts and online services for unusual activity are also recommended steps.
In conclusion, the recent hacking incident has highlighted vulnerabilities in telecommunications security, prompting SK Telecom to take swift action to protect its customers. While the company has initiated a comprehensive response to the crisis, the challenges faced by customers in accessing these services underscore the need for ongoing vigilance and robust cybersecurity measures.
