A Russia-linked hacking group claimed responsibility for a recent cyberattack that crippled major Japanese video streaming website niconico, posting a statement on the dark web Thursday.
It was not immediately clear whether the statement by the group purporting to be BlackSuit ransomware gang was true or not.
The hackers threatened that they have gained access to "very personal information regarding Japanese citizens" and "everything will go public" on Monday unless Kadokawa Corp., the parent company of niconico operator Dwango Co., pays a ransom.
Kadokawa, a major Japanese publisher, declined to comment on the latest development.
On June 8, servers located in Kadokawa group's data center experienced a significant cyberattack ,including ransomware, targeting niconico and related services, according to the company.
Kadokawa has been investigating information leakage following the incident, but it has explained that it does not retain any credit card information of its group's customers, including niconico service users, in its system and no such breach has taken place.
Users can share videos ranging from music to animals on niconico and they can also watch the live streaming of government officials' press conferences.
