A recent cyberattack has put the personal information of millions of South Korean mobile users at risk. SK Telecom, the country’s largest mobile service provider, has confirmed that a major data breach has affected up to 25 million customers. The attack was carried out using malware that could allow criminals to perform SIM swapping — a method where someone takes control of a person's phone number to access their accounts and data.

The company said it is still investigating the situation but assured the public that no misuse of the stolen data has been confirmed so far. Despite this, many customers are worried that the real damage could still happen in the future.

In response to the breach, a group of victims has come together to demand answers and action. This group, calling itself the “SKT USIM Hacking Joint Response,” says SK Telecom has not been clear about how serious the breach is. They fear that leaked phone numbers and related information could be used to break into other services, such as bank accounts, messaging apps, and social media platforms — all of which often use phone numbers for verification.

To ease concerns, SK Telecom has promised to provide free replacement SIM cards to all affected users. However, the company has run into challenges with supply. So far, it has only secured one million SIM cards and plans to get five million more by the end of May. This is far from enough to cover the 25 million people impacted, so it may take a while before everyone receives their replacement card.

SK Telecom has set up an online system where customers can book appointments to get their new SIM cards. But the company has warned that long wait times should be expected because of the high demand.

This incident has raised serious questions about mobile security and how quickly companies respond to digital threats. As people rely more on their smartphones for banking, shopping, and communication, protecting mobile data has never been more important.