Daijiworld Media Network - Seoul

Seoul, May 5: SK Telecom has temporarily suspended all new subscriber registrations across South Korea as it works to contain the fallout from a recent large-scale data breach involving mobile phone USIM chips.

The suspension, which began Monday, follows an April 18 cyberattack that raised concerns over a potential mass leak of customer data tied to USIM cards — the chips that authenticate mobile users on networks. In response, the government ordered SK Telecom to freeze new sign-ups until the supply of USIM cards stabilizes.

To safeguard users, the telecom giant is offering free USIM replacements to its 25 million customers, including 2 million budget plan subscribers. However, the company has faced delays due to a shortage of replacement chips. So far, around 1 million users have completed the swap, while another 7.7 million have registered to do so.

As a temporary measure, SK Telecom has also introduced a USIM Protection Service that offers a similar level of defense against illegal financial activity, such as fraud and identity theft. The company reports that over 22 million users have already activated this digital safeguard.

To assist international travelers — who are not eligible for the digital protection service — SK Telecom has set up booths at Incheon International Airport to provide on-site USIM replacements.

SK Telecom CEO Ryu Young-sang stated, “From May 5, our 2,600 retail locations will pause new mobile subscriptions and focus solely on USIM card replacements. The suspension will continue until the supply issue is resolved.”

In addition, mobile number portability (MNP) transfers from rival carriers have also been put on hold. While the breach has not yet resulted in any confirmed cases of financial loss, SK Telecom says it remains on high alert.