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Nippon Medical School Musashi Kosugi Hospital

netrunner

This record tracks a ransomware attack claimed by the netrunner group against Nippon Medical School Musashi Kosugi Hospital. 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.

73days open
t1 · Published t2 · Pending
Apr 03, 2026Not disclosed yet
Country
Japan
Business Category
Healthcare / Medicine
Employees
+1000
Discovered
2026-04-03
Published
April 03, 2026
Disclosed / Notified
Not disclosed yet
Victim ID
9wtveOJGkx8g

Attack Summary

Nippon Medical School Musashi Kosugi Hospital is a 372-bed regional teaching hospital in Nakahara-ku, Kawasaki (Musashi-Kosugi area), affiliated with Nippon Medical School. Established in 1937, it offers comprehensive services across 36 clinical departments, including emergency and critical care, ICU, NICU, perinatal and pediatric care, cancer treatment, and minimally invasive endovascular procedures. The hospital serves as a regional hub with disaster-resistant facilities and an on-site heliport, and emphasizes advanced, patient-centered care and medical education.

Leak Screenshots

SAMPLE

Proof-of-breach screenshots the operator posted from the stolen data. Previews are redacted and locked — the originals are available on HaveIBeenRansom.

file_tree.png
finance_2024.xlsx
passport_scan.jpg
contract_signed.pdf
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Dark Web Exposure

Cross-referenced against HaveIBeenRansom's dark-web index of ransomware leaks, breaches & infostealer logs.
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found in Infostealer logs
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found in Traditional breaches
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found in Ransomware leaks
Emails exposed
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Full exposure is locked
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