DisclosureLens
GLOBALMalwareHealthcareHealthcareRansomwareNetrunnerRansom DemandedActor NamedMedium

Nippon Medical School Musashi Kosugi Hospital

bd_59eacc9f6b44be0c · schema v1 · pii pii-v1

Severity

Medium

Discovered

Filed

Apr 3, 2026

To disclose

Affected

Not disclosed

Confidence

50%
Full breach record for Nippon Medical School Musashi Kosugi Hospital

Threat-actor claim — not a regulatory filing

This row is a claim by the ransomware group Netrunner on its public extortion blog. It has not been validated by the victim or any regulator. Treat attribution and counts as the threat actor's assertion until a regulatory filing or victim disclosure corroborates them.

Group activity: HealthcareDiscovered: 2026-04-03

Source: Ransomware.live

Post text · scraped from the leak site

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.

Incident timeline — mostly unverified

? — ?

Breach window unknown

Apr 3, 2026

Claim posted

No filing yet · watching

Compliance clocks stay unassessable until a regulatory filing lands. Dashed segments fill in automatically when corroboration arrives.

Claim → filing

Compliance clock

Not assessable

Tracked as a single-filing incident — the only disclosure on record for this event so far.Unverified claimView incident

Evidence ladder

Leak-site claimThis record

Attacker assertion only. Establishes: claim date, group, alleged victim.

Press / market report

Unlocks: incident narrative, operational impact. Still no compliance clock.

State AG / regulator filing

Unlocks: discovery date, data types, affected count, compliance clock.

SEC 8-K / victim statement

Unlocks: materiality, stated response, full audit trail. Ceiling removed.

No regulatory filing corroborates this yet — it is the attacker's own assertion. Watch this entity to be notified the moment a filing corroborates or contradicts it.

Source ceiling

  • actor name
  • victim claim
  • ransom/leak status
  • discovery date
  • materiality
  • notification
  • affected count
  • confirmed data types
  • compliance clock

The ✕ fields stay blank until a regulatory filing or victim disclosure lands.

About this groupFirst seen 2026-04-03

netrunner

According to ransomware.live, NetRunner is a ransomware group active from at least 2025 targeting diverse sectors including healthcare, telecommunications, manufacturing, and agriculture across Japan, Italy, the US, and Jordan, notably demanding a $100M ransom from Nippon Medical School Musashi Kosugi Hospital.

6 victims claimed globally6 tracked hereFull profile →