Japanese publisher Kadokawa has confirmed a data leak affecting 254,241 people due to a cyberattack.
The finding, announced Monday, is based on an investigation by third-party experts.
Of the leaked data, information of 186,269 people was related to Kadokawa Dwango Educational Institute, including N High School, a correspondence school. Kadokawa reported the investigation results to the government's Personal Information Protection Commission.
Leaked information also included data on all employees of Dwango Co., a Kadokawa unit that operates the Niconico video-sharing platform, as well as the names and addresses of business partners such as artists and designers.
Regarding the school institution, data of current students, their guardians, graduates and exam applicants was breached, as was contract information of Dwango's business partners.
According to the investigation, phishing attacks are thought to have enabled the theft of employee account information and caused the leak, and the stolen account data had allowed the group's internal network to be hacked.