sponichi.co.jp Domain Breach Exposure Report

The domain sponichi.co.jp has experienced a significant number of data breaches, totaling 448 events, which constitute 87.2% of all observed events over the reporting period. Additionally, there were 66 infostealer events, representing 12.8% of the total. The timeline indicates a surge in client-related events starting in August 2025 and peaking in April 2026, with employee-related events also increasing in September 2025 and again from March to June 2026. Malware analysis shows Redline, LummaC2, and Raccoon as prevalent, often associated with targeted login services on the sponichi.co.jp domain. The majority of data exposure originates from "Combolist sources" (96.2%), suggesting credential stuffing or similar attacks, with a smaller portion from "Database dumps". The high volume of historical data breaches and active infostealer logs, coupled with the targeting of login services, indicates a substantial risk of credential compromise for both employees and clients. The prevalence of Redline and LummaC2 malware further exacerbates this risk by facilitating the exfiltration of sensitive information. Prioritization should focus on immediate remediation of identified vulnerabilities in login portals, enhancing authentication mechanisms, and conducting thorough investigations into the source of the combolists and database dumps to prevent further exploitation.