> JapanHacked_
[Contained][Severity: Critical][Ransomware][Intrusion]

F-one: ransomware attack

Encryption and a ransom note discovered on January 30 were disclosed on February 4. The April final report found unauthorized VPN connections on January 26 and 28 and compromised administrator privileges. F-one concluded that about 170,000 personal records leaked, although retained logs could not establish outbound transfer and some logs were lost or encrypted. The count may include duplicate people. Card data was not held.

Disclosed

2026-02-04

Organizations involved

1

Leaked or at risk

170K

170,000

Downtime

Unknown

Timeline

  1. Started 2026-01-26
  2. Detected 2026-01-30
  3. Disclosed 2026-02-04
  4. 9 days

Organizations involved

Open in organization search

Sources

  1. [1][Official]ランサムウェア攻撃に関するお知らせとお詫び(第1報)F-one Limited · 2026-02-04
  2. [2][Official]ランサムウェア攻撃に関するお知らせとお詫び(第2報)F-one Limited · 2026-02-25
  3. [3][Official]ランサムウェア攻撃に関するお知らせとお詫び(最終報)F-one Limited · 2026-04-08