Was atg.cz hit by ransomware?

atg.cz was listed by the warlock ransomware operation (Czechia), 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 warlock ransomware group?

warlock 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 atg.cz breach?

warlock published data attributed to atg.cz. Darkfield captured the leak post and a screenshot of the listing.

Ransomware victim disclosure

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ATG (Advanced Testing Group)

listed as atg.cz · Claimed by Warlock · listed 7 months ago

Age

since listed · data leaked

Status timeline

ListedNov 6, 2025
Data leakeddate unknown

At a glance

Group: Warlock
Status: Data leaked
Country: Czechia
Sector: Technology
Listed on leak site: Nov 6, 2025

About the victim

AI dossier — public-source company profile

ATG is a Czech-based company and one of the largest NDT-oriented companies worldwide, with approximately 30 years of history in the field of non-destructive testing. The company provides complete solutions for NDT by offering both products (ET, FPI, MPI, UT, RT systems and equipment) and services (testing, inspection, personnel qualification, consultancy) across industries including aerospace, automotive, energy, and railways. ATG operates as a group with subsidiaries including ATG Slovakia and LA composite.

Industry: Non-Destructive Testing (NDT) Equipment & Services

Attack summary

Severity: high — Data has been confirmed published (data_published status) by the threat actor. ATG serves aerospace, automotive, energy, and railways sectors with NDT qualification and certification services; exfiltrated data could include proprietary testing methodologies, customer/client records, personnel qualification data, and sensitive industrial inspection results. The industrial and safety-critical nature of the sectors served elevates severity.

The Warlock ransomware group claims a successful attack on ATG (atg.cz) with the disclosure status marked as data_published, indicating data has been exfiltrated and published. No further description of the attack vector, encrypted systems, or specific data categories was provided in the leak post.

high

Data the group says was taken

AI dossier — extracted from the leak post

Published company data (type unspecified)

What the group claims

No description provided.

Sources

Victim siteatg.cz

Source

Indexed 7 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 warlock

Warlock is an emerging ransomware group that first appeared in June 2025, primarily motivated by financial gain through extortion operations targeting organizations across multiple sectors. The group's origin and potential affiliations remain unclear due to limited public documentation from established threat intelligence sources, though their targeting pattern spans both Western nations and Russia, suggesting possible opportunistic rather than geopolitically-motivated operations. Based on available victim data, Warlock has demonstrated capability to compromise organizations across diverse sectors including technology, financial services, telecommunications, and healthcare, with their attack methodology and technical capabilities requiring further analysis by security researchers to establish definitive patterns regarding initial access vectors, encryption methods, or data exfiltration tactics. While the group has accumulated 78 documented victims across the United States, Japan, Russia, Great Britain, and Turkey within their initial months of operation, insufficient public reporting from CISA, FBI, or major security firms exists to detail specific notable campaigns, ransom demands, or high-profile incidents. Given the group's recent emergence in mid-2025, their current operational status and potential evolution remain under observation by the cybersecurity community. The group has been linked to 78 public disclosures across our corpus. First observed on a leak site on June 11, 2025; most recent post November 6, 2025. The operation is currently inactive.

Timeline of this disclosure

November 6, 2025atg.cz listed by warlockon the group's public leak site

Other recent disclosures by warlock

warlock has been linked to 78 public victims on Darkfield. A sample of the most recent:

See the full warlock dossier →

Sector and geography

This disclosure adds to ransomware activity in the Technology sector, which has 3,544 disclosures indexed across all operators we track. Geographically, atg.cz is reported in Czechia, a country with 15 ransomware disclosures in our corpus.

If your organisation is affected

A listing by warlock means atg.cz 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 warlock'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.