Disclosure context

About J

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. The group has been linked to 41 public disclosures across our corpus. First observed on a leak site on May 2, 2025; most recent post November 9, 2025. The operation is currently inactive.

Timeline of this disclosure

September 29, 2025Petro-Diamond (petrodiamond.com) - subsidiary of Mitsubishi Corporation listed by Jon the group's public leak site

Sector and geography

This disclosure adds to ransomware activity in the Energy sector, which has 374 disclosures indexed across all operators we track. Geographically, Petro-Diamond (petrodiamond.com) - subsidiary of Mitsubishi Corporation is reported in Japan, a country with 108 ransomware disclosures in our corpus.

How we know this. Darkfield monitors public ransomware leak sites continuously, archiving every new disclosure and the data later released against the victim. Each entry on this page is sourced from the operator's own publication and cross-checked against complementary OSINT feeds (RansomLook, ransomware.live, RansomWatch). We do not collect or host stolen data — only the metadata, timestamps and screenshots needed to make the public disclosure searchable and accountable. Records here are corrected when the original post is edited, retracted, or merged with another disclosure.

Ransomware victim disclosure

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Petro-Diamond (petrodiamond.com) - subsidiary of Mitsubishi Corporation

Claimed by J · listed 8 months ago

Age

since listed · data leaked

Status timeline

Listed
Sep 29, 2025
Data leaked

At a glance

Group: J
Status: Data leaked
Country: Japan
Sector: Energy
Listed on leak site: Sep 29, 2025

About the victim

AI dossier — public-source company profile

Petro-Diamond is a commodity trading subsidiary of Mitsubishi Corporation, headquartered in Japan. The company is engaged in the trade and marketing of petroleum and its derivatives, liquefied petroleum gas (LPG), carbon-related materials, and petrochemicals. It also participates in energy project development activities.

Industry: Petroleum & Commodity Trading

Attack summary

Severity: high — Data has been confirmed as published by the threat actor against a subsidiary of a major multinational (Mitsubishi Corporation) operating in the energy and commodity trading sector, which likely involves sensitive business, contractual, and financial data; however, no specific regulated PII at scale or critical infrastructure disruption is confirmed, keeping this below critical.

The group J claims to have published data belonging to Petro-Diamond; the disclosure status is listed as data_published, indicating exfiltration and public release of company data, though no specific ransom demand or data volume has been stated.

high

Original description

AI-summarised, not from the leak post

Petro-Diamond is a commodity trading subsidiary of Mitsubishi Corporation. It's involved in the trade and marketing of petroleum and its derivatives, liquefied petroleum gas (LPG), and carbon-related materials. Also, they handle petrochemicals and participate in energy project developments.

Sources

Source

Indexed 8 months ago

This page surfaces a public ransomware disclosure indexed by Darkfield. Original posts come from the operator's own leak site; we cross-check against ransomware.live, RansomLook and RansomWatch where applicable. Share this URL freely.