> JapanHacked_Cybersecurity incidents in Japan

Company

Mouse Computer Co., Ltd.

Mouse Computer Co., Ltd. (Chiyoda, Tokyo; Manufacturing) appears in 3 related cybersecurity incidents. The latest was disclosed on 2026-10-07.

Profile

Industry/type: Manufacturing
Location: Tokyo, Chiyoda
Website: https://www.mouse-jp.co.jp/

Public figures

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Metric	Value	Scope	As of	Source
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Incident history

Disclosed 2026-10-07Updated 2026-10-27 19:58Aichi, Fukuoka, Hiroshima, Ibaraki, Osaka, Tokyo[Ongoing][Severity: Critical][Through a supplier][Moderate]
IDC Frontier: ransomware attack on IDCF Cloud
[Ransomware][Intrusion][Web app exploit][Service outage][Data leak]Leaked 4MOrganizations 495
Disclosed 2021-07-06Updated 2021-07-09 08:00Tokyo[Resolved][Severity: Major][Breached][Major]
Mouse Computer: its product review tool was accessed without authorization, and email addresses and purchased product names of customers and partners leaked
[Intrusion][Data leak]Organizations 1
Disclosed 2020-05-13Updated 2020-05-20 08:00Tokyo[Resolved][Severity: Major][Breached][Major]
Mouse Computer: a phished staff mailbox sent fake emails to 1,220 business customers and partners
[Phishing][Credential abuse][Data leak]Organizations 1

		Incident	Role	Impact level				Methods	Impacts		Status
2026-10-07	2026-10-27 19:58	IDC Frontier: ransomware attack on IDCF Cloud	[Through a supplier]	[Moderate]	[Critical]	495 IDC Frontier Inc., Central Japan Railway Company, East Japan Railway Company, Ibaraki Prefectural Government, Ibaraki Prefectural Police, Kyushu Railway Company, Izumi Co., Ltd., Nissui Corporation, Daihatsu Motor Co., Ltd., Mouse Computer Co., Ltd., PEACH JOHN Co., Ltd., SKY Perfect JSAT Corporation, Soliton Systems K.K.	Aichi, Fukuoka, Hiroshima, Ibaraki, Osaka, Tokyo	[Ransomware][Intrusion][Web app exploit]	[Service outage][Data leak]	4,030,000	[Ongoing]
2021-07-06	2021-07-09 08:00	Mouse Computer: its product review tool was accessed without authorization, and email addresses and purchased product names of customers and partners leaked	[Breached]	[Major]	[Major]	1 Mouse Computer Co., Ltd.	Tokyo	[Intrusion]	[Data leak]	Unknown	[Resolved]
2020-05-13	2020-05-20 08:00	Mouse Computer: a phished staff mailbox sent fake emails to 1,220 business customers and partners	[Breached]	[Major]	[Major]	1 Mouse Computer Co., Ltd.	Tokyo	[Phishing][Credential abuse]	[Data leak]	Unknown	[Resolved]