Was MatTek hit by ransomware?

MatTek was listed by the thegentlemen ransomware operation (United States), 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 thegentlemen ransomware group?

thegentlemen 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 MatTek breach?

thegentlemen published data attributed to MatTek. Darkfield captured the leak post and a screenshot of the listing.

Ransomware victim disclosure

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MatTek Corporation

listed as MatTek · Claimed by Thegentlemen · listed 6 days ago

Age

since listed · data leaked

Status timeline

ListedJul 23, 2026
Data leakeddate unknown

At a glance

Group: Thegentlemen
Status: Data leaked
Country: United States
Sector: Manufacturing
Listed on leak site: Jul 23, 2026

About the victim

AI dossier — public-source company profile

MatTek Corporation is a biotechnology company founded in 1985 and headquartered in Ashland, Massachusetts. It specializes in developing innovative in vitro 3D reconstructed human tissue models and advanced microtissues used by researchers for drug development, toxicity testing, and alternatives to animal testing. The company was recently acquired by Sartorius and now operates as part of their advanced biological models portfolio.

Industry: Biotechnology & Life Sciences – In Vitro Tissue Models
Address: Ashland, Massachusetts, US
Founded: 1985

Attack summary

Severity: medium — Data has been published by the threat actor (disclosed status: data_published), indicating confirmed exfiltration. However, the leak post provides no specific details about data sensitivity, volume, or regulated content (no mention of PII, medical records, financial data, or government information). The company operates in biotech/pharmaceuticals, which typically involves sensitive IP and research data, but without explicit confirmation of what was compromised, this merits medium rather than hig

The threat actor claims to have breached MatTek and published data. The post does not explicitly state whether data was encrypted, exfiltrated, or both, nor does it detail the specific data categories compromised.

medium

Data the group says was taken

AI dossier — extracted from the leak post

Research and development records
Business documents
Corporate records

What the group claims

***.com zoominfo.com/c/mattek-corp/109184324 MatTek Corporation is a pioneering biotechnology company founded in 1985 and headquartered in Ashland, Massachusetts, specializing in the development of innovative in vitro 3D reconstructed human tissue models. They produce advanced microtissues and cell culture products that are widely used by researchers to accelerate drug development, conduct toxicity testing, and replace traditional animal testing. Originally an independent leader in tissue engineering, the company was recently acquired by the global life science supplier Sartorius and now operates as a key part of their advanced biological models portfolio

Sources

Victim sitemattek.com

Source

Indexed 6 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.

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Disclosure context

About thegentlemen

thegentlemen is a ransomware group that emerged in September 2025, operating with apparent financial motivations based on their broad targeting of commercial sectors. The group has documented 267 victims across multiple countries, with primary focus on the United States, Thailand, France, Brazil, and India. Their targeting strategy demonstrates a preference for high-value sectors including manufacturing, technology, healthcare, and financial services organizations. Given the group's recent emergence and limited public documentation from established threat intelligence sources such as CISA, FBI, or major security research firms, specific details regarding their country of origin, operational structure, attack methodologies, encryption techniques, and whether they employ ransomware-as-a-service models remain unclear. The relatively high victim count of 267 in a short operational timeframe since September 2025 suggests either an aggressive campaign pace or potential inflation of victim numbers through affiliate operations, though without corroborating intelligence reports, the group's exact operational capabilities and notable campaigns cannot be definitively established. Current intelligence indicates the group remains active as of late 2025, though comprehensive threat profiling requires additional validated reporting from authoritative cybersecurity sources. The group has been linked to 655 public disclosures across our corpus. First observed on a leak site on September 9, 2025; most recent post July 28, 2026. The operation is currently active.

Also tracked as: the gentlemen.

Timeline of this disclosure

July 23, 2026MatTek listed by thegentlemenon the group's public leak site

Other recent disclosures by thegentlemen

thegentlemen has been linked to 655 public victims on Darkfield. A sample of the most recent:

See the full thegentlemen dossier →

Sector and geography

This disclosure adds to ransomware activity in the Manufacturing sector, which has 3,684 disclosures indexed across all operators we track. Geographically, MatTek is reported in United States, a country with 3,138 ransomware disclosures in our corpus.

If your organisation is affected

A listing by thegentlemen means MatTek 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.
Report the incident to your national CERT, CISA (United States), as required for your jurisdiction.
Monitor for the data appearing on thegentlemen'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.