Omnibus Japan: ransomware hit the Tohokushinsha group company, encrypting some files; publication of client information on a leak site was confirmed

Omnibus Japan, a Tohokushinsha group company, was hit by ransomware that encrypted some files, and client information was confirmed published on a leak site.

Disclosed

2025-12-17

Organizations involved

Leaked or at risk

Unknown

Downtime

Unknown

What happened

2025-12-09
It confirmed a cyberattack using ransomware on part of its systems, which encrypted some files and made them inaccessible. It asked an external specialist to investigate and set up a joint task force with Tohokushinsha. [1]
2025-12-17
It announced the unauthorized access by ransomware (first report). [1]
2025-12-26
It published a second report. [1]
2026-06-04
It published the sixth report. The data was posted on the leak site, but no sign that files were taken out has been confirmed. [2]

ScanNetSecurity reported that publication of client information on a leak site was confirmed. [1]

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[Breached][Moderate]Tokyo, Minato-kuInformation and communications
Omnibus Japan Inc.

						Note
Omnibus Japan Inc.	[Breached]	[Moderate]	Tokyo, Minato-ku	Information and communications	Unknown