According to reports from Min Shi News, South Korea's telecommunications giant SK Telecom was invaded by hackers starting June 2022, where they used ransomware 'Qilin' (also known as Agenda) to extort a significant ransom from the company on the dark web. The subsequent investigation revealed shocking details: the hackers had been lurking within the company for nearly three years, leading to the leak of nearly 27 million mobile user personal data.

On April 29, SKT confirmed the discovery of four malicious programs that had stolen user-related USIM card data, prompting the company to announce the replacement of SIM cards for over 25 million users. The latest report revealed that 9.82 GB of data had been leaked, including 26,957,749 international mobile subscriber identities (IMSI).

Cybersecurity experts highlight that hacker attacks vary between disruptions and data theft, with a growing trend towards using data theft to extort companies. To avoid detection while gathering substantial data, hackers require extended periods for infiltration. This underscores the need for companies to fortify security measures, including encrypting databases and sensitive files.