SK Telecom post-hack USIM replacement program thwarted by shortage

Home > National > Social Affairs

SK Telecom post-hack USIM replacement program thwarted by shortage

Published: 28 Apr. 2025, 14:21 Updated: 28 Apr. 2025, 19:52

Audio report: written by reporters, read by AI

A notice on a SK Telecom store in Seoul reads that there are no more USIM cards in stock on April 27. [YONHAP]

An SK Telecom store in Seogyo-dong, Mapo District, western Seoul, was spotted with a notice that read “Replacement USIM cards are out of stock” at around 11:20 a.m. on Sunday.

Following SK Telecom’s disclosure of a mass-scale USIM (Universal Subscriber Identity Module) hacking incident, customers continued to flock to stores over the weekend. Upon seeing the notice that USIM cards were out of stock, many expressed their frustration, either turning away or asking whether reservations were possible.

“We sold out all 20 or so USIM cards we had in just one day on Friday,” said a store employee. “We probably won’t get new stock until early May.”

Possible fallout from the incident is intensifying customer anxiety and dissatisfaction. Although the company announced it would offer free USIM card replacements to all who request them, concerns about secondary crimes are fueling what some are calling a looming “USIM card crisis.”

People line up outside a SK Telecom store in Seoul to switch out their USIM cards on April 28. [YONHAP]

SK Telecom to secure 5 million USIM cards by May

Starting Monday, SKT will offer free USIM card replacements to any of its approximately 25 million subscribers, including 1.87 million budget phone users. While demand is difficult to predict, SK Telecom is preparing for the possibility that all customers may wish to replace their cards and is working to secure sufficient inventory.

Currently, SK Telecom has about 1 million USIM cards in stock and plans to secure an additional 5 million by the end of next month. USIM cards for SK Telecom are manufactured by four companies, including Xcure and SK Telink.

The industry expects a rush, beginning on Monday. SK Telecom operates about 2,600 T World stores nationwide, including directly operated and authorized dealerships, and 14 roaming centers, including eight at Incheon International Airport. Even if only 10 percent of customers — about 2.5 million people — seek replacements, each store would need to handle an average of 100 customers.

A notice on a SK Telecom store in Seoul reads that there are no more USIM cards in stock on April 27. [YONHAP]

In metropolitan areas, where more subscribers are concentrated, bottlenecks are likely to be even worse. To reduce inconvenience, SK Telecom recommends checking in advance by phone whether a store can process a replacement or reserving a time slot beforehand.

“We also plan to accept online reservations,” said an SK Telecom official. “Customers will be able to choose a store and will be served in order.”

Customers unable to visit stores in person are expressing frustrations.

Song Kyung-seop, 54, a resident of Osan, Gyeonggi, said he spent the weekend worrying about his in-laws, who both use SK Telecom and suffer from dementia, making it impossible for them to visit a store without assistance.

“My wife and I both work, so it’s impossible to travel two hours to my in-laws' home during the week,” said Song. “But the nearby store told us new stock wouldn't arrive until next week.

“I’m going crazy worrying they might fall victim to phishing calls.”

A phone screen shows a cue of over 110,000 people on an online SK Telecom service for switching USIM on April 28. [YONHAP]

SK Telecom recommends USIM protection service

For customers unable to immediately replace their USIM cards, SK Telecom is recommending enrollment in its USIM protection service. The free service blocks unauthorized phone activations and fraudulent payment attempts using illegally cloned USIM cards.

As of 6 p.m. on Sunday, about 5.54 million customers had enrolled in the protection service, according to SK Telecom.

“Just signing up for this service can almost completely prevent damages from USIM information leaks,” said the company, promising full liability for any damages suffered after enrollment.

However, customers must cancel any active roaming services before enrolling, causing further inconvenience. SKT said it plans to improve the service by mid-May to allow enrollment without canceling roaming services.

Despite USIM card replacements, anxiety over potential secondary crimes remains high among users.

On social media, posts urging customers to replace their USIM cards and sign up for the protection service are spreading rapidly, warning that hacked USIM information could allow for unlimited device cloning.

The surge in users trying to sign up for identity protection services caused access delays on “PASS,” the authentication app shared by Korea’s three telecom providers, on Sunday.

A notice on a SK Telecom store in Seoul reads that there are no more USIM cards in stock on April 27. [YONHAP]

SK Telecom maintains that replacing the USIM card significantly reduces the risk of hacking-related abuses.

“When you replace the USIM, the identification number changes and no longer matches the subscriber’s phone number,” said an SK Telecom official. “Cloning or activating a new phone becomes impossible.

“There is no evidence that sensitive information such as names or resident registration numbers was leaked, so risks of fraudulent payments or other criminal activities are low.”

However, if additional personal information beyond USIM data is found to have been leaked later, or if secondary hacking attacks occur, the risk of crimes combining leaked data could rise.

Acting President Han Duck-soo orders full review and response

Acting President Han Duck-soo issued an emergency directive on Sunday, instructing the Ministry of Science and ICT and other agencies to thoroughly review SK Telecom’s countermeasures, such as the USIM Protection Service and card replacements, and to focus on minimizing public inconvenience.

The Ministry also warned that phishing scams are already attempting to exploit the situation by luring users to fake sites under the guise of “free USIM replacements” and “USIM Protection Service” offers, urging the public to exercise caution.

Translated from the JoongAng Ilbo using generative AI and edited by Korea JoongAng Daily staff.
BY YUN JUNG-MIN, OH HYEON-WOO, JUN-YUL [kim minyoung5@joongang co kr]