RansomHouse ransomware group lists [EVIDENCE PACK 3]ASKUL on its leak site

• Ransomware group: RansomHouse
• Country: Japan
• Sector: Professional Services
• Announcement date: December 2, 2025

RansomHouse claims to have stolen data from ASKUL

The threat actor known as RansomHouse has listed the Japanese e-commerce company ASKUL on its dedicated leak site. According to the group's announcement, the company has been targeted in a cyberattack, and the group claims to have successfully exfiltrated a significant amount of data from the organization's systems.

The group alleges that the incident occurred on October 19, 2025. In their public announcement, which was posted on December 2, 2025, RansomHouse issued a warning to the management of ASKUL regarding the potential consequences of the breach. The group has threatened that the confidential data obtained during the attack could be sold to third parties or released publicly if their demands are not met.

Details of the alleged data exfiltration

While the threat actor has claimed to have stolen a substantial volume of information, specific details regarding the exact nature of the leaked data have not been provided in the announcement. The group has not disclosed the specific file types or the exact categories of information contained within the stolen files. However, the group has provided visual evidence in the form of a screenshot, which indicates that the stolen data is being organized and presented in three separate packages, which are labeled as 'Evidence Pack 3'.

The listing names no specific data types that have been compromised.

About ASKUL Corporation

ASKUL Corporation is a leading Japanese e-commerce company. The organization provides a wide range of products, including office supplies, daily goods, and medical products, to both business-to-business (B2B) and business-to-consumer (B2C) customers. Beyond product distribution, the company offers various digital and physical business solutions, including logistics, printing, and digital business services, through its primary platforms such as ASKUL and LOHACO.

Analysis and potential implications

This incident suggests that ASKUL's corporate data and customer information may be at risk of exposure. Given the RansomHouse group's focus on data exfiltration and extortion, it is possible that the leaked data could be utilized for identity theft or targeted phishing campaigns. The group's tactics are consistent with modern double extortion ransomware models, where attackers not only encrypt systems but also steal sensitive information to use as leverage during negotiations.

Under Japan's Act on the Protection of Personal Information (APPI), the organization may face mandatory breach notification requirements and potential regulatory penalties. Furthermore, the loss of trust in e-commerce operations could have negative implications for supply chain partners and end-users. Public information regarding the specific operations and identity of the RansomHouse group remains limited.

For organizations operating within the professional services and e-commerce sectors, such incidents highlight the importance of robust defensive measures. Common defensive steps often include implementing multi-factor authentication, maintaining rigorous patch management schedules, and conducting regular data backups. Additionally, organizations often focus on network segmentation and continuous monitoring to detect unauthorized data exfiltration attempts before they reach a critical scale.