SHINDO6

Shinchosha

Shinchosha Co., Ltd.

Personal data~102,700records

LEAK CONFIRMEDHealth / medical / treatment / Date of birthRansomware · Closed (final report)

Open in the live monitor ▶
Disclosed
Dec 9, 2025
Leak
Leak confirmed
Type
Ransomware
Status
Closed (final report)
Security spend
Not checked yet
Compensation
Not announced

What leaked

Transactions & activityPolicy or certificate number
IdentityFull name, Date of birth, Gender
ContactAddress, Phone number, Email address
Special-care dataMedical information

How many

  • Personal records from commissioned investigations confirmed leaked ~102,700 records
  • Policy or certificate numbers only ~89,000 records
  • Including names, dates of birth, addresses and more ~13,700 records
  • Including medical information ~1,200 records
  • Possibly leaked (commissioned work) ~1,030 records

Who is affected

  • Insurance and mutual aid policyholders and people involved in claims

Cause

An external cyberattack encrypted files stored on some servers with ransomware

Timeline

  1. Intrusion began
  2. First announcement date not confirmed; date of the Security NEXT report on the investigation results

Response

  • Forensic investigation

What you should do

  1. Health data can't be taken back. Don't answer blackmail; call the police (#9110) or the consumer hotline (188)
  2. Don't open links in emails from this company. The apology email itself may be fake
  3. Treat refund or apology calls and texts as scams. Call back only on the number from the official site
  4. Watch for unexpected mail or invoices; your address is hard to change
  5. 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