SHINDO4

Seed Planning

Personal data~130,000records

POSSIBLE LEAKPostal address / Full nameRansomware · Investigating

Open in the live monitor ▶
Disclosed
Mar 6, 2026
Detected
Mar 2, 2026
Detection to disclosure
4 days
Leak
Leak possible
Type
Ransomware
Status
Investigating
Security spend
Not checked yet
Compensation
Not announced

What leaked

Transactions & activityWater usage volume
Account dataCustomer number
ContactAddress
IdentityName of the user

How many

  • Records from the Tokyo Waterworks survey work ~130,000 records

Who is affected

  • Tokyo Waterworks water users

Cause

Unauthorized access to servers and devices, and ransomware infection

Timeline

  1. System failure caused by ransomware found
  2. Tokyo Waterworks and Seed Planning announced

Response

  • Blocked the entry point
  • Forensic investigation

Cut off the whole network as an emergency step against spread, and started an outside expert investigation

What you should do

  1. Watch for unexpected mail or invoices; your address is hard to change
  2. 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