This record tracks a ransomware attack claimed by the
qilin group against
Mutsumi Group. It collects the publicly disclosed attack details — sector, location and
timeline — as published on the operator's leak site and indexed by Breach House.
Window Zero
EXPOSURE GAP
Window Zero is the time the breach stayed in the open before
anyone said so — the gap between when the attack was first discovered
on the operator's leak site (t1) and when it was publicly disclosed (t2).
The wider this window, the longer victims, staff and customers were exposed with no warning.
0days open
t1 · Published
t2 · Pending
Business Category
Services
Indexed by Breach House
October 04, 2026
Leak Status
pending
checked 2026-10-04
Disclosed / Notified
Not disclosed yet
Attack Summary
www.mutsumi-g.co.jp operates within Japan’s Services sector and functions as a commercial entity providing service-oriented offerings under its domain identity. Within the threat-intelligence index, this entity is cataloged as a ransomware victim linked to the qilin threat actor. The listing reflects its classification in relation to a cyber incident involving ransomware activity, without disclosing unverified details such as data stolen, ransom demands, or confirmed breach specifics. This entry serves to document the association for security professionals monitoring service-sector exposure in Japan. The designation remains neutral, focusing solely on the verified relationship between the entity and the identified threat actor.
Leak Screenshots
1 CAPTURED
Captured directly from the operator's leak site by our collector, last checked 2026-10-04. Verdict evidence: [M1] COMPANY URL | OCT 4, 2026 | 219 | 8 photos
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Dark Web Exposure
Cross-referenced against HaveIBeenRansom's dark-web index of ransomware leaks, breaches & infostealer logs.
0
found in Infostealer logs
0
found in Traditional breaches
0
found in Ransomware leaks
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Full exposure is locked
See every breached email, the internal-vs-external split and each leak source behind this victim.
Legal Disclaimer:
This ransomware victim record reflects information published on the operator's leak site.
Breach.house only records what the operators themselves publish in the
open. We take screenshots of their public pages and keep the proof
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