chatwork.com Domain Breach Exposure Report

The telemetry indicates a significant exposure event impacting chatwork.com, with a high risk score of 95. The primary concern stems from 47,159 historical data breaches, predominantly originating from combolist sources, and 8,810 active infostealer logs. These events suggest a widespread compromise of credentials, potentially affecting over 55,000 clients and 145 employees. The timeline shows a notable increase in employee-related events in early 2026, particularly in March and April, coinciding with a surge in client-related exposures. The prevalence of infostealer malware families like Redline, LummaC2, and Rhadamanthys, alongside the targeting of chatwork.com login pages, points to a coordinated effort to harvest credentials. The majority of affected users are located in Japan. Given the high volume of data breaches and active infostealer activity, immediate investigation into the scope of credential compromise and potential unauthorized access is critical. Remediation should focus on credential reset for all potentially affected employees and clients, enhanced monitoring of login activity, and strengthening authentication mechanisms.