On June 8, 2024, Kadokawa Corporation’s websites and its Dwango-owned video platform Niconico began suffering a major outage. Kadokawa confirmed on June 14 that ransomware was responsible after attackers repeatedly restarted servers despite remote shutdown attempts, forcing the company to physically disconnect power and network cables. The Russian-linked group BlackSuit claimed responsibility on June 27 and threatened to publish 1.5 terabytes of stolen business-partner and user data unless a ransom was paid. Kadokawa later said a phishing attack was a possible initial cause.
The incident disrupted Niconico programming through the end of July, delayed e-book distribution, temporarily halted publishing and manufacturing operations, and disabled Kadokawa’s online shop. The company’s stock price fell more than 20% by July 3, while Niconico and Kadokawa services did not fully return until August 5. On August 6, Kadokawa disclosed that information belonging to 254,241 people had leaked, including 186,269 individuals connected to Kadokawa Dwango Educational Institute. On December 12, BlackSuit claimed Kadokawa had paid $2.9 million in cryptocurrency. Kadokawa rebuilt systems and introduced additional security measures, while warning that redistribution of leaked information could trigger legal action.
