Hacker Group Claims Responsibility for Cyberattack on Japanese Video Site Niconico; Group Threatens to Release Stolen Data if Demands Not Met

Yomiuri Shimbun file photo

A cyberattack has forced Japanese video-sharing site Niconico to suspend operations and a hacking group has claimed responsibility for the attack, it has been learned.

The group, which calls itself “BlackSuit,” claimed to have encrypted the systems of Niconico operator Dwango Co. and its parent company, major publisher Kadokawa Corp., and stolen customer and employee data.

In a statement posted on its website on Thursday, the hackers said they stole about 1.5 terabytes of data, including Kadokawa’s financial documents and contracts, according to sources in the security field. They also disclosed documents believed to be part of the materials they stole.

The group also issued a ransom demand and is threatening to release the entire set of stolen data on July 1 if their demands are not met.

“We have no response at this time,” a Kadokawa official told The Yomiuri Shimbun.