SHINDO3

Tokyo Gas Network Co., Ltd.

Customer records~20,000records

POSSIBLE LEAKPostal address / Phone numberLoss · Investigating

Open in the live monitor ▶
Disclosed
Aug 13, 2026
Detected
Aug 6, 2026 00:30 JST
Detection to disclosure
7 days
Leak
Leak possible
Type
Loss
Status
Investigating
Security spend
Measures, no amount
Compensation
Not announced
Corporate number
1010401159334

What leaked

IdentityFull name
ContactAddress, Phone number, Email address

Not leaked

  • No financial institution data was on the laptop

How many

  • Customer records ~20,000 records
  • Customers who asked for a city-gas supply study 152 records

Who is affected

  • Customers whose gas work was completed
  • Customers who asked for a city-gas supply study

Cause

After drinking with colleagues, an employee lost a bag with the work laptop and other items on the train home. The laptop cannot be used without the employee's ID and password

Timeline

  1. Bag lost on the train home
  2. The employee noticed the loss around 00:30 on August 6 and told a manager that morning
  3. First disclosure

Response

  • Hotline

Toll-free line 0120-600-848 from August 14

What you should do

  1. Don't open links in emails from this company. The apology email itself may be fake
  2. Treat refund or apology calls and texts as scams. Call back only on the number from the official site
  3. Watch for unexpected mail or invoices; your address is hard to change
  4. 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