Disclosure context

About chaos

Based on the limited publicly available information, Chaos is a recently emerged ransomware group that was first observed in March 2025, appearing to be financially motivated given their ransom demands and targeting patterns. The group's origin and specific affiliations remain unclear due to their recent emergence, though their operational model and whether they operate as Ransomware-as-a-Service or as an independent entity has not been definitively established by security researchers. Their attack methodology and specific technical capabilities are not yet well-documented in public threat intelligence reports, though their targeting suggests they employ common initial access vectors to compromise victims across multiple sectors. Chaos has claimed 41 victims primarily concentrated in the United States, Germany, Poland, Malaysia, and Sweden, with a particular focus on technology companies, financial services, business services, and manufacturing sectors, though the scope and impact of their most significant attacks have not been widely publicized. The group currently appears to be active based on recent victim claims, though comprehensive analysis from major security firms regarding their long-term operational capabilities and potential law enforcement actions remains limited due to their recent emergence in the threat landscape. The group has been linked to 53 public disclosures across our corpus. First observed on a leak site on March 31, 2025; most recent post May 17, 2026. The operation is currently active.

Timeline of this disclosure

December 2, 2025lesker.com listed by chaoson the group's public leak site

Sector and geography

This disclosure adds to ransomware activity in the Technology sector, which has 2,524 disclosures indexed across all operators we track. Geographically, lesker.com is reported in United States, a country with 7,392 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

Kurt J. Lesker Company

listed as lesker.com · Claimed by chaos · listed 6 months ago

Age

since listed · data leaked

Status timeline

Listed
Dec 2, 2025
Data leaked

At a glance

Group: chaos
Status: Data leaked
Country: United States
Sector: Technology
Listed on leak site: Dec 2, 2025

About the victim

AI dossier — public-source company profile

Kurt J. Lesker Company (KJLC), founded in 1954, is a leading manufacturer and distributor of high-quality vacuum products, including vacuum chambers, pumps, flanges, thin-film deposition systems, sputter targets, and related components. The company serves electronic, communications, semiconductor, and research industries globally, with operations across North America, Europe, and Asia. It also offers services such as pump repair, precious metal reclaim, and custom chamber fabrication.

Industry: Vacuum Equipment Manufacturing & Distribution
Employees: 201-500
Founded: 1954

Attack summary

Severity: high — Data has been published by the threat actor, indicating confirmed exfiltration. KJLC serves semiconductor, electronics, defense, and research sectors globally; exposure of customer, order, or technical data from such a supplier carries significant business and supply-chain risk.

The Chaos ransomware group claims an attack on Kurt J. Lesker Company and has published data (disclosed status: data_published), asserting access to company data associated with its vacuum equipment manufacturing and sales operations. No ransom amount or specific data volume was stated in the post.

high

Data the group says was taken

AI dossier — extracted from the leak post

Company business data
Customer and order information
Internal operational files

What the group claims

Since it's foundation in 1954, Kurt J. Lesker Company has manufactured and sold vacuum equipment and parts to the electronic and communications related industries

Sources

Source

Indexed 6 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.