Ransom! Nostrum (MAY-2026)

Ransom! Nostrum (MAY-2026)
Thegentlemen claim to have compromised Nostrum Corporation (nostrum.co.jp) in Japan, encrypting systems and threatening to leak data as part of a ransomware operation. Nostrum, founded in 1991 and represented by Ryoichi Jono, is a Japanese technology company involved in smartphone app development, web system development, and website construction, cited in the claim as the affected party.
#Japan

Incident Details

  • Victim: Nostrum
  • Sector: Not Found
  • Country: JP
  • Actor: thegentlemen
  • Source:
  • Discovered: 2026-05-06T10:08:41.895526+00:00
  • Published: 2026-04-27T11:09:00+00:00

Information

  • Nostrum Corporation (nostrum.co.jp) — based in Japan, founded in 1991
  • Specializes in smartphone app development, web system development, and website construction
  • Representative: Ryoichi Jono
  • Registered and verified on the J-GoodTech platform as a Japanese technology business
  • Flagship product: job aptitude test preparation tool — a simulation platform replicating SPI, TG-WEB, and similar employment exam interfaces used by major Japanese companies
  • Ransomware actor involved: thegentlemen

Disclaimer: This post is based on public claims made by the ransomware group "thegentlemen". I cannot confirm the accuracy of the information. However, I would be happy to share any official statement from the affected organization to provide clarification.

monitored by: ransomware.live