The government issued a security reinforcement advisory after confirming the existence of a "hacking forum" that siphon off and sell data from the country's health care and educational institutions, as well as online shopping platforms.

The Ministry of Science and ICT and the Korea Internet and Security Agency said on Wednesday that an unidentified hacking group recently extorted and sold such data from small-sized websites through the hacking forum.

A hacking forum refers to an online community where illegal cyber activities take place, such as sharing of hacking information, sale of extorted data and dissemination of malignant codes.

According to the ministry, 17 institutions and companies were targeted in the serial hacking attacks between December 2025 and January 5, excluding the recent data breach at e-commerce giant Coupang.

Authorities urged the institutions and the companies to bolster security inspections and to exercise caution to prevent future attacks and further damage.