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Kurogane Kasei Co., Ltd.

listed as Kurogane Kasei Co. · Claimed by Ransomhouse · listed 9 months ago

743 GB
Data size
193 employees records
$740
Ransom
demanded
8m
Age
since listed · data leaked

Status timeline

  1. ListedOct 23, 2025
  2. Data leakeddate unknown

At a glance

Group
Ransomhouse
Status
Data leaked
Country
Japan
Sector
Manufacturing
Listed on leak site
Oct 23, 2025
Data size
743 GB
Records
193 employees
Ransom demanded
$740

About the victim

AI dossier — public-source company profile

Kurogane Kasei Co., Ltd. (黒金化成株式会社) is a Japanese specialty chemical company headquartered in Nagoya, Aichi Prefecture, specializing in organic synthetic chemistry, contract synthesis and manufacturing, and functional materials development. The company operates multiple facilities including the Minokamo Factory, Chiryu Factory, and a Technical Center (KTC), serving customers across electronics, plastics, and medical/pharmaceutical sectors. It is a member of the KH Neochem Group.

Industry
Organic Synthetic Chemistry & Specialty Chemical Manufacturing
Address
〒460-0003 愛知県名古屋市中区錦1-6-17（本社）

Attack summary

Severity: high — 743 GB of confirmed exfiltrated data from a specialty chemical manufacturer with R&D and proprietary synthesis operations; data is marked as published/disclosed, and the company itself acknowledged unauthorized server access publicly.

RansomHouse claims to have exfiltrated approximately 743 GB of data from Kurogane Kasei's servers; the company's own public website confirmed unauthorized access to its servers in notices published in October 2025. The group has listed the data as published/disclosed.

high

Data the group says was taken

AI dossier — extracted from the leak post
  • Corporate server data
  • Potentially proprietary synthesis/R&D data
  • Business operational files
  • Potentially personal information (per company privacy policy revisions)

What the group claims

Kurogane Kasei Co., Ltd. is a development-oriented Japanese chemical company specializing in organic synthesis and fine chemicals production. Its core activities include joint R&D projects, entrusted synthesis, and scalable production from gram-level prototypes to ton-scale manufacturing. The company caters to industries such as electronics, pharmaceuticals, and agrochemicals, leveraging advanced technologies like esterification and specialized equipment for dust-free, metal-free environments. With a workforce of about 193 employees, Kurogane Kasei positions itself as an 'all-round player' in the chemical sector, prioritizing customer satisfaction through rapid prototyping and innovative solutions.

The leak post

captured from the group's site
```
{"data":[{"id":"a1894b76b7004c75a3a0845799af49956592e3d9","display":"animated","header":"HOT NEWS","info":" Trellix is a global cybersecurity company.","url":"","sort":1,"views":"436242"},{"id":"336b257f582b17573c97578efd4b22762bf77344","sort":2,"header":"Trellix (McAfee & FireEye)","url":"https://www.trellix.com/","private":"false","revenue":"1.5-2 B$","employees":"5000","info":"Trellix is a global cybersecurity company formed from the October 2021 merger of McAfee Enterprise and FireEye. It provides services to over 50,000 business and government customers worldwide, protecting more than 200 million endpoints. The companys open and native extended detection and response (XDR) platform helps organizations confronted by todays most advanced threats gain confidence in the protection and resilience of their operations. Trellix, along with an extensive partner ecosystem, accelerates technology innovation through machine learning and automation to empower over 40,000 business and government customers with living security","statusDate":"DEPENDS ON YOU","status":"EVIDENCE","published":"NOT YET","action":"Encrypted","actionDate":"17/04/2026","volume":"~","content":"cybersecurity.html"…

Sources

Source

Indexed 9 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.

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Disclosure context

About Ransomhouse

Ransomhouse is a ransomware group that emerged in June 2021, operating primarily for financial gain through extortion campaigns targeting organizations across multiple sectors globally. The group's origin and specific affiliations remain unclear based on publicly available intelligence, though their operational patterns suggest they function as an independent cybercriminal organization rather than a traditional ransomware-as-a-service model. Ransomhouse employs double extortion tactics, stealing sensitive data before deploying their ransomware payload and threatening to publish the information on their leak site if victims refuse to pay the demanded ransom. The group has demonstrated a broad targeting approach, with documented attacks against 187 victims primarily concentrated in the United States, China, United Kingdom, Italy, and Spain, focusing heavily on healthcare, technology, business services, and manufacturing sectors. While specific high-profile campaigns have not been extensively documented by major security firms, the group's consistent victim count and geographic distribution indicate sustained operational capability since their emergence. As of current reporting, Ransomhouse remains active with no known major law enforcement disruptions or confirmed rebranding efforts. The group has been linked to 210 public disclosures across our corpus. First observed on a leak site on June 1, 2021; most recent post June 29, 2026. The operation is currently active.

Also tracked as: RANSOM HOUSE.

Timeline of this disclosure

  • October 23, 2025Kurogane Kasei Co. listed by Ransomhouseon the group's public leak site
Data size
743 GB
Records
193 employees
Ransom demanded
$740

Other recent disclosures by Ransomhouse

Ransomhouse has been linked to 210 public victims on Darkfield. A sample of the most recent:

See the full Ransomhouse dossier →

Sector and geography

This disclosure adds to ransomware activity in the Manufacturing sector, which has 3,681 disclosures indexed across all operators we track. Geographically, Kurogane Kasei Co. is reported in Japan, a country with 220 ransomware disclosures in our corpus.

If your organisation is affected

A listing by Ransomhouse means Kurogane Kasei Co. appeared on a ransomware extortion site and data attributed to it has been published. If this is your organisation, or a supplier you depend on, the priority is to confirm the intrusion and contain it before the window to act closes.

  • Engage your incident-response team and preserve forensic evidence before remediating — do not wipe affected systems first.
  • Force a password reset and revoke active sessions for exposed accounts; rotate any credentials, API keys or certificates that may have been in the stolen data.
  • Assess regulatory notification duties (GDPR, NIS2, sector regulators) — many carry a 72-hour reporting clock from awareness.
  • Report the incident to your national CERT, JPCERT/CC (Japan), as required for your jurisdiction.
  • Monitor for the data appearing on Ransomhouse's leak site and across paste and breach channels, and brief downstream partners who may be exposed through you.

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.