Disclosure context

About coinbasecartel

CoinbaseCartel is a ransomware group that emerged in September 2025 with financially motivated operations targeting organizations across multiple sectors and geographic regions. The group has demonstrated significant activity in a short timeframe, compromising at least 102 known victims primarily across the United States, United Arab Emirates, Germany, Canada, and Brazil. Their targeting patterns show a preference for technology companies, financial services organizations, manufacturing entities, and consumer services businesses, suggesting an opportunistic approach focused on organizations likely to have both valuable data and the financial resources to pay ransoms. Given the group's recent emergence and limited public documentation from established threat intelligence sources, details regarding their specific attack methodologies, infrastructure, and organizational structure remain largely unconfirmed by major cybersecurity firms or law enforcement agencies. The group appears to maintain active operations as of late 2025, though comprehensive analysis of their tactics, techniques, and procedures awaits further investigation and reporting by established threat intelligence organizations. The group has been linked to 176 public disclosures across our corpus. First observed on a leak site on September 15, 2025; most recent post May 16, 2026. The operation is currently active.

Also tracked as: coinbase cartel.

Timeline of this disclosure

April 18, 2026Altpro listed by coinbasecartelon the group's public leak site

Sector and geography

This disclosure adds to ransomware activity in the Not Found sector, which has 4,859 disclosures indexed across all operators we track. Geographically, Altpro is reported in Croatia, a country with 4 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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Altpro

Claimed by coinbasecartel · listed 1 month ago

32d

Age

since listed · data leaked

Status timeline

Listed
Apr 18, 2026
Data leaked

At a glance

Group: coinbasecartel
Status: Data leaked
Country: Croatia
Sector: Not Found
Listed on leak site: Apr 18, 2026

About the victim

AI dossier — public-source company profile

Altpro is a Croatian company specialising in signal-safety systems for railway infrastructure and rolling stock, including train detection, axle counters, level-crossing protection, and ETCS/ATP onboard systems. With over 30 years of experience, it exports to more than 55 countries across 6 continents and employs over 200 engineers and specialists across 5 regional locations. Its products are certified to SIL 4 international safety standards and have been deployed in projects with partners such as Bombardier/Alstom and CRRC.

Industry: Railway Signalling & Safety Systems
Address: Croatia (headquarters; 5 regional locations globally)
Employees: 200+

Attack summary

Severity: high — Altpro operates in critical railway safety infrastructure (SIL 4 certified systems) across 55+ countries. Even without detailed leak post content, a confirmed data-published status against a critical-infrastructure supplier operating internationally represents a significant threat; any exfiltrated data could include proprietary safety-system designs, project documentation, or partner/client data relevant to national rail networks.

The coinbasecartel ransomware group has listed Altpro as a victim with a disclosed/published status, claiming data has been published; however, no ransom amount, data volume, or detailed leak post content was provided, making it impossible to confirm the scope or nature of the exfiltration or encryption.

high

Original description

AI-summarised, not from the leak post

N/A

The leak post

captured from the group's site

System Breach • Coinbasecartel We are looking for new partners/insiders. Send us a message to dicuss We are looking for new partners/insiders. Send us a message to dicuss CRITICAL ANNOUNCEMENTS &times; Contact Update We have changed our contact method. We now exclusively use qTox Messenger for all communications. SimpleX and Session have been discontinued. Our Tox ID: A7580331D4D16453CCE86D7ADFBCF0CEED0D0D1AEA8F4DBEEBCA9E3B46308F260DE9B41BD838 TO APTIM You may have noticed the sudden, heavy silence. The corporate VPNs are dead. We have been the silent architects of your network for the past three weeks. While your &#34;elite&#34; investigators from Mandiant sat in your logs, we sat directly beside them burning through over a hundred of your corporate identities like disposable tools. we have had your entire network and internal protocols. HOW LONG WILL YOU KEEP YOUR THOUSANDS OF FIELD WORKERS LOCKED OUT? We have successfully exfiltrated the most sensitive engineering data held by any firm in your sectors We hold the complete Navisworks 3D models, P&amp;ID diagrams, and maintenance logic for your major energy plants. This includes the granular Honeywell DCS controller logic. We know…

Sources

Victim sitealtpro.hr
Leak posthttp://fjg4zi4opkxkvdz7mvwp7h6goe4tcby3hhkrz43pht4j3vakhy75znyd.onion/companies/altpro

Source

Indexed 1 month 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.