Cyber Incident Victim: Cabinet Office of Japan
Date:
Apr 2018
Location:
Japan
Summary
A significant data breach impacted Japan's Cabinet Office and multiple government ministries, compromising sensitive employee credentials. The National Center of Incident Readiness and Strategy for Cybersecurity alerted ministries after discovering thousands of email addresses and associated passwords being sold on dark web marketplaces. Approximately 2,100 employees across foreign affairs, economic, internal affairs, transport, and other ministries had their login credentials exposed, including those used for membership websites. The leaked data was identified by cybersecurity firm KELA through monitoring of illicit online platforms.
| CIA Posture | Motives | Tactics, Techniques & Procedures |
|---|---|---|
| Available to members | 1 motive | 1 technique |
| Threat Actors | Type | Location |
|---|---|---|
| 0 actors | Available to members | Available to members |
Description
On or around April 4, 2018, Japan’s National Center of Incident Readiness and Strategy for Cybersecurity (NISC) issued a warning to all government ministries regarding a significant data breach. The center confirmed that email addresses and passwords belonging to thousands of employees across multiple ministries had been compromised and were being actively traded on dark web marketplaces. The leaked data reportedly included credentials from approximately 2,100 employees working within the foreign, economy, internal affairs, transport, and other unspecified ministries. Cybersecurity firm KELA, based in Israel, identified the exposed information on illicit "dark sites" and alerted authorities. The breach involved not only government email addresses but also passwords employees used to access membership websites, suggesting potential vulnerabilities in non-governmental platforms. NISC’s alert emphasized the immediate risks posed by the exposure of these credentials, though it did not specify whether the leak originated from government systems or third-party services.
The incident exposed sensitive authentication details that could facilitate unauthorized access to government-related accounts or affiliated systems. While the full scope of operational disruptions remained unclear, the sale of credentials on underground forums heightened concerns over espionage, phishing campaigns, or further network intrusions. NISC coordinated with affected ministries to assess the breach’s impact and initiate credential resets or security enhancements. No public statements attributed the attack to specific threat actors or detailed the initial intrusion vectors. The breach underscored systemic challenges in securing employee credentials across interconnected government and external platforms, though subsequent containment measures were not disclosed in available reports. The incident marked one of Japan’s most significant government-related data leaks at the time, prompting internal reviews of authentication practices and dark web monitoring protocols.