tenki.jp Domain Breach Exposure Report

The telemetry indicates a significant exposure related to the domain tenki.jp, with a high volume of historical data breaches (475) and active infostealer logs (105) observed over the period from July 2025 to June 2026. The data breaches are primarily sourced from "Combolist sources," suggesting credential stuffing or account takeover attempts. The infostealer activity involves malware families such as LummaC2, Redline, and Acreed, which are known for exfiltrating sensitive information. The timeline shows a notable increase in both employee and client-related events, particularly in March, April, and June 2026, coinciding with the peak of observed data breaches and infostealer activity. The risk score of 74 suggests a high priority for remediation. The prevalence of data breaches from combolists and the active use of infostealers targeting the domain, including specific services like tenki.jp and its login endpoints, indicate a substantial risk of credential compromise and potential downstream impacts. Focus should be placed on strengthening authentication mechanisms, monitoring for credential stuffing attacks, and investigating the source and scope of the historical data breaches to prevent further exploitation.