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Darkfield

Operator dossier

J is a ransomware operator no longer publishing new disclosures. Darkfield has indexed 41 public victims claimed by this operator between May 2, 2025 and November 9, 2025. The J ransomware group is a newly emerged threat actor first observed in May 2025, operating with apparent financial motivations based on their targeting patterns across multiple countries and sectors. With limited public documentation available from established security research organizations, the group has demonstrated rapid operational capability by compromising 41 known victims within their initial months of activity. Their targeting strategy appears opportunistic, focusing primarily on organizations in the United States, United Kingdom, France, Argentina, and Germany, with a particular emphasis on technology companies, manufacturing firms, construction businesses, and business services providers. The diversity of their geographic and sectoral targeting suggests either a broad-spectrum approach to victim selection or potential use of automated tools for initial compromise identification. Given the recent emergence of this group and limited reporting from major cybersecurity firms and law enforcement agencies, specific details regarding their technical methodologies, ransom demands, data exfiltration practices, or organizational structure remain undocumented in publicly available threat intelligence. The group remains active as of current reporting periods, though their relative obscurity in established threat intelligence databases suggests they may be operating at a smaller scale compared to more prominent ransomware-as-a-service operations.

Most-targeted sectors

Most-affected countries

Recent disclosures by J

All 41 indexed disclosures. Click any row for the full per-victim dossier.

See every disclosure indexed for J →

How we know this. Operator profiles on Darkfield are built from continuous monitoring of every leak site the group is known to operate, cross-correlated with community-curated feeds (RansomLook, ransomware.live, RansomWatch, MISP-galaxy). Status flips from active to inactive when no new disclosure appears for 60 days. MITRE ATT&CK mappings shown in the interactive section below are sourced from CISA, vendor analysis, and the MITRE community catalog — we attribute each technique back to its source. Aliases reflect operator re-brands and affiliate splits.

Inactive ransomware operator

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J

41 victims indexed · first seen 1 year ago · last activity 8 months ago

41
Victims indexed
#120 of 364 tracked operators
6m
Active period
May 2025 → Nov 2025
10
Countries hit
top US · 6

At a glance

Status
inactive
First seen
1 year ago
Last activity
8 months ago
Primary sector
Not Found · 14 hits

About

The J ransomware group is a newly emerged threat actor first observed in May 2025, operating with apparent financial motivations based on their targeting patterns across multiple countries and sectors. With limited public documentation available from established security research organizations, the group has demonstrated rapid operational capability by compromising 41 known victims within their initial months of activity. Their targeting strategy appears opportunistic, focusing primarily on organizations in the United States, United Kingdom, France, Argentina, and Germany, with a particular emphasis on technology companies, manufacturing firms, construction businesses, and business services providers. The diversity of their geographic and sectoral targeting suggests either a broad-spectrum approach to victim selection or potential use of automated tools for initial compromise identification. Given the recent emergence of this group and limited reporting from major cybersecurity firms and law enforcement agencies, specific details regarding their technical methodologies, ransom demands, data exfiltration practices, or organizational structure remain undocumented in publicly available threat intelligence. The group remains active as of current reporting periods, though their relative obscurity in established threat intelligence databases suggests they may be operating at a smaller scale compared to more prominent ransomware-as-a-service operations.

Timeline

7 months
2025-05-01T00:00:00+00:00 · 142025-06-01T00:00:00+00:00 · 92025-07-01T00:00:00+00:00 · 42025-08-01T00:00:00+00:00 · 42025-09-01T00:00:00+00:00 · 72025-10-01T00:00:00+00:00 · 12025-11-01T00:00:00+00:00 · 2
2025-05-01T00:00:00+00:002025-11-01T00:00:00+00:00

Top countries

🇺🇸 United States
6
🇬🇧 United Kingdom
3
🇫🇷 France
3
🇦🇷 Argentina
3
🇩🇪 Germany
3
🇮🇳 India
3
🇧🇷 Brazil
2
🇯🇵 Japan
2
United States dossier →United Kingdom dossier →France dossier →Argentina dossier →

Top sectors

Technology
6
Manufacturing
5
Construction
5
Business Services
2
Transportation/Logistics
2
Education
2
Public Sector
2
Energy
2
Technology dossier →Manufacturing dossier →Construction dossier →Business Services dossier →

MITRE ATT&CK

9 techniques · 4 tactics

Tactics

Command And ControlExecutionInitial AccessStealth

Techniques

Recent victims

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Source

Updated 8 months ago

Data on this page is sourced from the group's own leak posts, cross-checked with public ransomware trackers (RansomLook, ransomware.live, RansomWatch), MITRE ATT&CK, and our own Tor and Telegram crawlers. This is a public observatory page — share freely.

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