ARAARA Email Service Exposed 3 Million Customer Email Addresses

| 2026-10-30 10:29 HIGH LOW DATA BREACH

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Executive Summary

Highlight CTI
AI-generated

A Japanese email service company, Arara, has suffered a data breach after approximately 3,010,000 of its customer email addresses were leaked due to unauthorized access to its email service, Arara Message. The incident occurred on October 28 and was announced by the company on October 29. Released email addresses may be used for corporate impersonation phishing emails or malicious code distribution, posing a risk. The breach is classified as a data breach cyber operation type. Japanese authorities are likely involved in investigating this incident. Security experts emphasize that domestic companies should verify the scope and storage period of personal information provided to external email sending services. This incident highlights concerns about phishing and impersonation attacks on multiple customers whose email addresses were leaked, with approximately 3 million customer email addresses exposed.

Technical Mitigations AI-generated

• Patch the web server to address the exploited vulnerability, specifically focusing on the Arara Message email service. • Inspect and strengthen server access controls for subcontractors handling customer information. • Verify the storage period of personal data provided to external services like Arara.

Intelligence Metadata

Actors / Malware / CVEs / Campaigns

Target & Sectors

Incident Timeline

‎October 28

Threat actors used social engineering to target Japanese email sending service ARAARA, resulting in the exposure of approximately 3 million customer email addresses.

‎October 29

Arara announced the incident on October 29 through an official statement, revealing that unauthorized access to its server system had resulted in the leak of approximately 3,010,000 email addresses.

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general_metric 3,010,000 email addresses

Arara announced the incident on October 29 through an official statement, revealing that unauthorized access to its server system had resulted in the leak of approximately 3,010,000 email addresses.

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