Disclosure context

About beast

The Beast ransomware group is a relatively new threat actor that emerged in July 2025, operating with apparent financial motivations through their ransomware campaigns. With limited public documentation available from major security agencies, the group has demonstrated activity primarily targeting victims across the United States, United Kingdom, Brazil, South Korea, and Argentina, accumulating approximately 65 known victims since their emergence. Their targeting pattern shows a focus on healthcare organizations, manufacturing companies, educational institutions, and construction firms, suggesting an opportunistic approach rather than highly specialized sector expertise. The group's recent emergence means there is insufficient public intelligence from CISA, FBI, Mandiant, or other established security researchers regarding their specific attack methodologies, initial access vectors, or technical capabilities. Given the timeline of their first observation in mid-2025, Beast represents an active and emerging threat with their current operational status remaining unclear due to limited threat intelligence reporting from authoritative sources. The group has been linked to 74 public disclosures across our corpus. First observed on a leak site on July 29, 2025; most recent post May 20, 2026. The operation is currently active.

Timeline of this disclosure

May 20, 2026ACMARK s r o listed by beaston the group's public leak site

Sector and geography

This disclosure adds to ransomware activity in the Repair Services sector. Geographically, ACMARK s r o is reported in Czech Republic, a country with 10 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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ACMARK s r o

Claimed by beast · listed 23 hours ago

Today

Age

since listed · listed for ransom

Status timeline

Listed
May 20, 2026

Current state: Listed for ransom

At a glance

Group: beast
Status: Listed for ransom
Country: Czech Republic
Sector: Repair Services
Listed on leak site: May 20, 2026

About the victim

AI dossier — public-source company profile

ACMARK s.r.o. is a small repair services company headquartered in Brno, South Moravian Region, Czech Republic. It employs between 10 and 19 people and generates annual revenue in the range of 1M to 5M (currency unspecified, likely CZK or EUR). No further operational details are publicly available.

Industry: Repair Services
Address: Brno, South Moravian, Czech Republic
Employees: 10-19

Attack summary

Severity: low — Only a listing/announcement with no proof files, no stated data exfiltration, no ransom amount, and no description of operational impact or sensitive data categories disclosed.

The Beast ransomware group has listed ACMARK s.r.o. as a victim, claiming an attack on the company. No specific details regarding encryption, exfiltration, or data types at stake have been provided in the post.

low

What the group claims

ACMARK s r o is a company that operates in the Repair Services industry. It employs 10 to 19 people and has 1M to 5M of revenue. The company is headquartered in Brno, South Moravian, Czech Republic.

The leak post

captured from the group's site

ACMARK s r o is a company that operates in the Repair Services industry. It employs 10to19 people and has 1Mto5M of revenue. The company is headquartered in Brno, South Moravian, Czech Republic.

Sources

Leak posthttp://beast6azu4f7fxjakiayhnssybibsgjnmy77a6duufqw5afjzfjhzuqd.onion/card/acmark

Source

Indexed 23 hours 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.