Kadokawa Corp. said Friday it confirmed that the personal information of all employees of its subsidiary operating the popular video streaming website niconico was leaked in a recent massive cyberattack affecting the group's websites.
The findings were announced a day after a group purporting to be a Russia-linked BlackSuit ransomware gang claimed responsibility for a cyberattack against Kadokawa's networks, insisting that it has stolen employee-related data and internal-use documents, among other information.
The Japanese publisher said it is still investigating the veracity of the group's claims.
According to Kadokawa, the leaked data also included client-related information such as contract agreements and personal details of some online content creators who use a support service provided by niconico operator Dwango Co., as well as Dwango's internal documents.
Police are investigating the case. Kadokawa also stated that a third-party organization is examining the data breach, and the findings are expected to be released in July.
According to Kadokawa, on June 8, servers located at its group's data center experienced a significant cyberattack involving a ransomware attack, which has disrupted niconico and related services.
Kadokawa apologized to the affected parties and said, "We will take preventive measures by reinforcing our information security system while strictly dealing with criminal acts, including ransomware attacks."
Credit card information of its group's customers, including niconico service users, has not been breached, according to Kadokawa.
