SHINDO4

Act Sen Co., Ltd.

RansomwareSize not disclosed

POSSIBLE LEAKID document (type not stated) / PasswordRecovering

Open in the live monitor ▶
Disclosed
Jun 15, 2026
Leak
Leak possible
Type
Ransomware
Status
Recovering
Security spend
Not checked yet
Compensation
Not announced

What leaked

IdentityName, Date of birth
Employment & HREmployee number
ContactEmail address, Company and personal phone numbers
CredentialsLogin passwords and initial email passwords
ID documentsLicence numbers and other qualification data

Who is affected

  • Employees
  • Former employees

Cause

The work-management server was accessed by a third party and infected with ransomware

Timeline

  1. First disclosure

Response

  • Service stopped
  • Blocked the entry point
  • Governance / committee

Stopped and isolated the server, reported to authorities, moving to a new environment and reviewing security

What you should do

  1. ID numbers can never be changed. Request your credit file from CIC, JICC and others and look for contracts or loans you didn't make
  2. Register a self-declaration (honnin shinkoku) with the credit bureaus so lenders check applications in your name more carefully. The stronger loan self-restriction scheme also blocks your own borrowing and can't be withdrawn for 3 months. Neither stops bank accounts being opened
  3. Change this password and every account that reused it now. Switch to a passkey where offered
  4. Don't open links in emails from this company. The apology email itself may be fake
  5. Treat refund or apology calls and texts as scams. Call back only on the number from the official site
  6. Expect targeted phishing posing as HR or interview contacts
  7. Check the company's notice to see if you're affected

Lessons for companies

  1. Offline backups with restore drills; segment the network
  2. Don't keep ID or bank data: delete after checks or use a KYC provider
  3. Report to the PPC: preliminary in 3–5 days, final in 30 (60 if malicious)
  4. Run red teaming and AI-assisted hardening, and publish how much you invest

Sources