SHINDO3

Takasu Town

Residents2,125people

LEAK CONFIRMEDPostal address / Date of birthMisdelivery · Closed (final report)

Open in the live monitor ▶
Disclosed
May 29, 2026
Detected
May 8, 2026
Detection to disclosure
21 days
Leak
Leak confirmed
Type
Misdelivery
Status
Closed (final report)
Security spend
Not checked yet
Compensation
Not announced

What leaked

IdentityName, Gender, Date of birth
ContactAddress

How many

  • Residents 2,125 people

Who is affected

  • Residents

Cause

When adjusting health-check lists, staff returned a list including residents unrelated to the provider

Timeline

  1. Detected
  2. Security NEXT report date

Response

  • Data deleted
  • Notified individuals
  • Staff training
  • Change process

Asked for deletion and confirmed it; sent apology letters; staff training and two-person checks

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. Use DLP: recipient checks, send delay, automatic attachment protection
  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