The giant Korean telco, SK Telecom Infected

Recently, SK Telecom, a major phone company in South Korea, was hacked, and customer data was stolen. SK Telecom is the largest wireless provider in South Korea, with millions of users and about half the market share.

The company posted a notice on Tuesday. They found out about the break-in on April 19. Hackers used malware to get personal information from customers.

To address this, SK Telecom offers a free service to protect SIM cards. This service helps prevent SIM swapping, as the stolen data might be used for these attacks.

The company acted quickly to remove the malware and separated the hacked parts of their system.

They're still investigating and have told the Korea Internet Security Agency about the breach.

It's unclear if this was a ransomware attack, a type of cyberattack where hackers hold data until paid. No groups have claimed responsibility yet.

Telecom companies like SK Telecom often face threats from government-backed hackers, mainly for spying. It's thought that China has been involved in many similar attacks on companies in the US and other places.