SHINDO2

Ibaraki Prefectural Mito Daiichi High School

Ibaraki Prefecture

LossSize not disclosed

POSSIBLE LEAKFull name / Profile fieldsClosed (final report)

Open in the live monitor ▶
Disclosed
May 20, 2026
Detected
Apr 17, 2026
Detection to disclosure
33 days
Leak
Leak possible
Type
Loss
Status
Closed (final report)
Security spend
Not checked yet
Compensation
Not announced

What leaked

IdentityStudent names
Account dataExam results and draft evaluations

Who is affected

  • Students of the school and its attached junior high

Cause

Data was saved to a USB stick, against the ban on taking personal data without permission, and the stick was lost

Timeline

  1. Data saved to a USB stick when the PC malfunctioned
  2. Detected
  3. First disclosure

Response

  • More monitoring
  • Governance / committee
  • Staff training

Monitoring for online leaks; strengthening data management and staff awareness

What you should do

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

Lessons for companies

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

Sources