Disclosure context

About apt73

APT73 is a recently emerged ransomware group that began operations in April 2024, with financial motivation as their primary driver based on their targeting patterns across multiple high-value sectors. The group has demonstrated rapid growth in their operational tempo, accumulating 78 documented victims within their first months of activity. Their targeting methodology shows a preference for English-speaking markets and major economies, with the United Kingdom and United States representing their primary focus areas, followed by significant activity in India, Brazil, and France. The group exhibits a clear preference for high-value sectors including business services, technology, financial services, and healthcare organizations, suggesting a calculated approach to victim selection based on potential payment capability and operational impact. Given the group's recent emergence and limited public documentation from major threat intelligence sources, specific details regarding their initial access vectors, tooling, encryption methods, or organizational structure remain largely unconfirmed by authoritative sources such as CISA, FBI, or established security research firms. The group's current operational status appears active based on the timeline of their emergence, though comprehensive analysis of their capabilities and infrastructure requires additional intelligence gathering and documentation by security researchers. The group has been linked to 141 public disclosures across our corpus. First observed on a leak site on April 22, 2024; most recent post April 27, 2026. The operation is currently inactive.

Also tracked as: Eraleign.

Timeline of this disclosure

April 27, 2026isosl.be listed by apt73on 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, isosl.be is reported in BE, a country with 28 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

← All victims

ISOSL

listed as isosl.be · Claimed by apt73 · listed 23 days ago

23d

Age

since listed · data leaked

Status timeline

Listed
Apr 27, 2026
Data leaked

At a glance

Group: apt73
Status: Data leaked
Country: BE
Sector: Not Found
Listed on leak site: Apr 27, 2026

About the victim

AI dossier — public-source company profile

ISOSL is a Belgian engineering company specialising in industrial solutions and automation. Based in Belgium, the company operates in the industrial engineering sector. Further details on scale and operations are not available from the provided sources.

Industry: Industrial Engineering & Automation

Attack summary

Severity: high — Data has been confirmed as published by the threat actor, indicating successful exfiltration of business data from an industrial engineering and automation company, which may include sensitive operational or proprietary technical information.

The group APT73 claims to have attacked ISOSL and has published data (disclosed status: data_published), suggesting exfiltration of company data, though specific details on encryption or precise data categories are not stated in the truncated post.

high

Data the group says was taken

AI dossier — extracted from the leak post

Industrial engineering data
Business operational data

What the group claims

ISOSL is an engineering company in Belgium, which deals with industrial solutions, automation and...

Sources

Victim siteisosl.be
Leak posthttp://basherq53eniermxovo3bkduw5qqq5bkqcml3qictfmamgvmzovykyqd.onion/page_company.php?id=140

Source

Indexed 23 days 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.