Was HARTMANN BAU hit by ransomware?

HARTMANN BAU was listed by the Dragonforce ransomware operation (Germany), and stolen data was published on the group's leak site. Darkfield tracks this disclosure with the original leak post, screenshot and group context.

Who is the Dragonforce ransomware group?

Dragonforce is a ransomware operator tracked by Darkfield. See the full operator dossier for its known victims, sectors targeted, IOCs and leak-site infrastructure.

What data was leaked in the HARTMANN BAU breach?

Dragonforce published data attributed to HARTMANN BAU. Darkfield captured the leak post and a screenshot of the listing.

Ransomware victim disclosure

← All victims

Nicol. Hartmann & Cie. AG

listed as HARTMANN BAU · Claimed by Dragonforce · listed 3 months ago

Age

since listed · data leaked

Status timeline

ListedMar 18, 2026
Data leakeddate unknown

At a glance

Group: Dragonforce
Status: Data leaked
Country: Germany
Sector: Construction
Listed on leak site: Mar 18, 2026

About the victim

AI dossier — public-source company profile

Nicol. Hartmann & Cie. AG (trading as Hartmann Bau) is a Swiss construction company with approximately 150 years of history, operating offices in St. Moritz and Chur, Switzerland. The company offers a broad range of services including structural construction (Hochbau), civil engineering (Tiefbau), waterproofing, plastering, turnkey buildings, garden construction, roofing, flooring, hazardous material remediation, and drainage cleaning. It operates as part of a larger group of companies.

Industry: General Construction & Building Services
Address: Via Surpunt 56, 7500 St. Moritz, Switzerland

Attack summary

Severity: high — Data has been confirmed as published (data_published status) by DragonForce, indicating actual exfiltration and public release of business data including financial, HR, and accounting documents, which constitutes significant confirmed data exposure.

DragonForce claims to have exfiltrated data from Nicol. Hartmann & Cie. AG and has published the data on their leak site. The disclosed status indicates data has been published, though no specific ransom amount or data volume was stated in the post.

high

Data the group says was taken

AI dossier — extracted from the leak post

Corporate correspondence
Financial documents
HR documents
Accounting documents
Contracts
Certificates

What the group claims

Hartmann Bau GmbH is a construction company based in Borgentreich near Kassel, specializing in residential, commercial, agricultural, and civil engineering projects in the Paderborn, Höxter, and Kassel areas. With over 80 years of experience, the company emphasizes quality, timely completion, and customer satisfaction as the foundation for successful construction projects. They offer a comprehensive range of services from planning to key handover, ensuring adherence to high standards and legal requirements. Their team is equipped to handle diverse projects, including offices, housing, barns, and warehouses, tailored to clients' specific needs

The leak post

captured from the group's site

```
{"data":{"count":483,"publications":[{"uuid":"b008b8b7-0e47-416f-adcd-2313d8136de4","created_at":"2026-05-08T20:56:13.122134Z","name":"CF Evans Construction","website":"www.cfevans.com","address":"125 Regional Pkwy Ste 200, Orangeburg, South Carolina, 29118, United States","description":"A recognized leader in the multi-family housing construction industry, CF Evans Construction provides a product for developers. The company has thrived amid six decades.\nThe data of this company includes:\n    Corporate correspondence of senior executives\n    Financial documents\n    HR documents\n    Accounting documents\n    Certificates, contracts, passwords, databases, and much more.","weight":4775795351552,"is_timer_publication_stopped":false,"timer_publication":"2026-05-22T07:48:00Z","try_again":false,"tags":[],"logo_uuid":"f4e582dd-6562-4590-bac8-2b9e5c564853","is_transfering":false},{"uuid":"3827192f-9bb3-490c-9c1c-d28b382510cd","created_at":"2026-05-08T17:53:24.736605Z","name":"CMC Expertise Comptable","website":"cmcexpertise.fr","address":"32 Rue De La Clairière, Fort-de-France,","description":"CMC Expertise Comptable is a certified accounting firm located in Martinique, dedicated t…

Sources

Source

Indexed 3 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 Dragonforce

Dragonforce is a relatively new ransomware group that emerged in December 2023, operating with apparent financial motivations based on their targeting patterns and victim selection. The group's origin and potential affiliations remain unclear due to limited public documentation from established threat intelligence sources, though their rapid accumulation of 439 documented victims suggests either sophisticated capabilities or possible connections to existing ransomware infrastructure. Based on their targeting patterns across diverse sectors including manufacturing, business services, technology, and construction, Dragonforce appears to employ opportunistic attack methodologies, though specific initial access vectors, encryption methods, and extortion tactics have not been publicly detailed by major security firms or law enforcement agencies. The group has demonstrated a preference for targeting organizations primarily in English-speaking countries and Western Europe, with the United States, United Kingdom, Germany, Australia, and Italy representing their most frequent victim locations, suggesting possible language capabilities or geographic operational preferences. As of current reporting, Dragonforce appears to remain active given their recent emergence and ongoing victim acquisition, though the lack of detailed public analysis from major threat intelligence organizations indicates either operational security measures that have limited researcher visibility or that the group has not yet conducted sufficiently high-profile attacks to warrant extensive public documentation by CISA, FBI, or established security research firms. The group has been linked to 596 public disclosures across our corpus. First observed on a leak site on December 13, 2023; most recent post June 12, 2026. The operation is currently active.

Timeline of this disclosure

March 18, 2026HARTMANN BAU listed by Dragonforceon the group's public leak site

Other recent disclosures by Dragonforce

Dragonforce has been linked to 596 public victims on Darkfield. A sample of the most recent:

See the full Dragonforce dossier →

Sector and geography

This disclosure adds to ransomware activity in the Construction sector, which has 415 disclosures indexed across all operators we track. Geographically, HARTMANN BAU is reported in Germany, a country with 695 ransomware disclosures in our corpus.

If your organisation is affected

A listing by Dragonforce means HARTMANN BAU 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.
Monitor for the data appearing on Dragonforce'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.