Was Jozef Stefan Institute (IJS) hit by ransomware?

Jozef Stefan Institute (IJS) was listed by the coinbasecartel ransomware operation (Slovenia), 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 coinbasecartel ransomware group?

coinbasecartel 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 Jozef Stefan Institute (IJS) breach?

coinbasecartel published data attributed to Jozef Stefan Institute (IJS). Darkfield captured the leak post and a screenshot of the listing.

Ransomware victim disclosure

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Jozef Stefan Institute (IJS)

Claimed by Coinbasecartel · listed 2 months ago

Age

since listed · data leaked

Status timeline

ListedMay 11, 2026
Data leakeddate unknown

At a glance

Group: Coinbasecartel
Status: Data leaked
Country: Slovenia
Sector: Education
Listed on leak site: May 11, 2026

About the victim

AI dossier — public-source company profile

Jozef Stefan Institute (IJS) is Slovenia's leading multidisciplinary research institution, headquartered in Ljubljana. It conducts fundamental and applied research across physics, chemistry, biochemistry, electronics, information technology, environmental sciences, and nuclear technology. It also trains postgraduate researchers and collaborates with national and international academic and industrial partners.

Industry: Scientific Research & Development
Address: Jamova cesta 39, 1000 Ljubljana, Slovenia
Employees: 1000-2000
Founded: 1949

Attack summary

Severity: high — Data is listed as published (confirmed exfiltration) from a nationally significant scientific research institution involved in nuclear technology, quantum computing, and defence-adjacent research; exfiltration of such research data carries significant national and scientific security implications even without explicit PII-at-scale confirmation.

The group 'coinbasecartel' claims to have published data exfiltrated from Jozef Stefan Institute, with the disclosure status listed as 'data_published'. No ransom amount or specific data volume has been stated in the post.

high

Data the group says was taken

AI dossier — extracted from the leak post

Research data
Employee records
Internal documents
Project/collaboration files

Original description

AI-summarised, not from the leak post

Jozef Stefan Institute (IJS) is Slovenia's leading research institution, headquartered in Ljubljana. It operates across multiple scientific disciplines including physics, chemistry, biochemistry, electronics, information technology, and environmental sciences. Founded in 1949, it conducts fundamental and applied research, hosts numerous national and international projects, and collaborates with academic and industrial partners. It also plays a key role in educating postgraduate researchers in Slovenia.

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 siteijs.si
Leak posthttp://fjg4zi4opkxkvdz7mvwp7h6goe4tcby3hhkrz43pht4j3vakhy75znyd.onion/companies/ijs

Source

Indexed 2 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 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 188 public disclosures across our corpus. First observed on a leak site on September 15, 2025; most recent post July 14, 2026. The operation is currently active.

Also tracked as: coinbase cartel.

Timeline of this disclosure

May 11, 2026Jozef Stefan Institute (IJS) listed by coinbasecartelon the group's public leak site

Sector and geography

This disclosure adds to ransomware activity in the Education sector, which has 1,082 disclosures indexed across all operators we track. Geographically, Jozef Stefan Institute (IJS) is reported in Slovenia.

If your organisation is affected

A listing by coinbasecartel means Jozef Stefan Institute (IJS) 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 coinbasecartel'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.