Hacker group RansomHouse claims responsibility for cyberattack on Nichirei

A hacker group calling itself RansomHouse has claimed responsibility for a cyberattack last week that disrupted operations at Japanese frozen-food and logistics company Nichirei, affecting restaurants, supermarkets and school lunch programs.

The group posted a statement on the dark web saying it had stolen internal Nichirei data, according to Nobuo Miwa, president of cybersecurity company S&J, who confirmed the posting Wednesday.

Nichirei has not identified the attacker nor confirmed the group’s claims. The Tokyo-based company said Wednesday that it was continuing to investigate the incident with an outside cybersecurity firm and was cooperating with police and other authorities.

Some affected servers contained personal information, and Nichirei said it had separately notified the people concerned. It did not disclose the type or volume of data potentially affected.

Nichirei first announced July 13 that it had detected system problems caused by unauthorized access. The company later confirmed that its servers had been targeted in a cyberattack.

The disruption interfered with incoming and outgoing shipments at refrigerated warehouses operated by Nichirei group companies, as well as deliveries of frozen-food products. Operations began gradually resuming July 17, and the company said all affected locations, including warehousing and frozen-food shipping facilities, were expected to return to normal this week.

One of the companies affected was Kentucky Fried Chicken Japan. The company said Wednesday that all of its restaurants had resumed normal operations after the disruption caused product shortages, restricted menus and shortened opening hours.

Ransomware attacks, which have been causing issues for multiple Japanese companies lately, typically involve encrypting data on computers or servers and demanding payment for its restoration or threatening to publish stolen information.

RansomHouse has previously claimed responsibility for attacks on several Japanese businesses, including a ransomware attack in October on office-supplies retailer Askul, which temporarily suspended services and later confirmed that customer and business partner information had been leaked.