Ransomware attacks in Japan: 379 confirmed incidents, 2018 to 2026

CONFIRMED RANSOMWARE ATTACKS · COUNTRY

Ransomnews has confirmed 379 ransomware attacks in Japan between October 2018 and October 2026, each one verified against a public source such as a breach notification, regulatory filing, court record or press report. That is 3.9% of the 9,715 confirmed incidents in the dataset. So far in 2026, 89 have been confirmed, against 93 in 2025 and 100 in 2024. The most affected sector is manufacturing, with 118 confirmed victims (31%). Tokyo is the city with the most confirmed victims, at 131. Where the operator is attributed, LockBit leads with 25 confirmed victims. A ransom payment is on the public record in 1 case and a refusal in 27; the outcome is unrecorded in the remaining 351.

Confirmed ransomware attacks in Japan by year

The current year is a partial count. Confirmation lags the attack itself, so recent months keep filling in after the fact; read a low figure for the latest year as incomplete rather than as a decline.

Which ransomware groups attack organisations in Japan most

The operator is attributed in 159 of the 379 confirmed incidents. Counts are confirmed victims, not leak-site claims, so they run well below the totals the groups publish about themselves. Group names link to the live Ransomtracker profile where one exists.

Where the confirmed attacks in Japan fall

Ransom payment outcomes in Japan

Among the 28 confirmed incidents in Japan where the outcome is on the public record, 1 paid and 27 refused, a disclosed payment rate of 3.6%. The remaining 351 carry no public statement either way. Victims that pay have every incentive to stay quiet and public bodies are the most likely to announce a refusal, so treat this as the disclosed rate, not the true one. The ransomware payment rate analysis explains how the disclosed rate has moved since 2018 and how it compares with incident-response firm samples.

Largest confirmed ransomware attacks in Japan by records exposed

Record counts are recorded only where a named source disclosed them, which is the minority of cases, so this table ranks disclosed impact rather than true impact.

Most recent confirmed ransomware attacks in Japan

The 25 most recently confirmed of 379 incidents, newest first. Every row links to the public source it was verified against.

Frequently asked questions

How to read this page. Every incident counted here was verified by Ransomnews against at least one public source. Leak-site listings alone do not qualify, because operators inflate, duplicate and occasionally fabricate claims, so these totals are a defensible floor rather than a full census. Records exposed and ransom outcomes appear only where a named source disclosed them. The page is regenerated from the live database, which refreshes weekly. Cite as: Ransomnews Confirmed Ransomware Attacks Dataset, ransomnews.com, with a link to this page. Bulk access and methodology questions: [email protected]. See also the monthly ransomware statistics and the Ransomtracker.