SHINDO2

Matsuzawa Shoten

RansomwareSize not disclosed

LEAK UNCLEARRecovering

Open in the live monitor ▶
Disclosed
May 18, 2026
Leak
Unknown
Type
Ransomware
Status
Recovering
Security spend
Not checked yet
Compensation
Not announced

What leaked

UnspecifiedWhether any data leaked was unknown at announcement

Who is affected

  • Client bookstores and others (details unknown)

Cause

Ransomware infection through unauthorized outside access; route not disclosed

Timeline

  1. Server intrusion and ransomware infection detected
  2. First disclosure
  3. Ordering on Gakufu Navi partly resumed

Response

  • Blocked the entry point
  • Password reset
  • Forensic investigation
  • BCP review

Isolated infected servers and devices, rebuilt servers and changed passwords; investigating with outside experts; resumed in stages with temporary email ordering

What you should do

  1. Check the company's notice to see if you're affected

Lessons for companies

  1. Offline backups with restore drills; segment the network
  2. Report to the PPC: preliminary in 3–5 days, final in 30 (60 if malicious)
  3. Run red teaming and AI-assisted hardening, and publish how much you invest

Sources