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 424 public disclosures across our corpus. First observed on a leak site on September 9, 2025; most recent post May 18, 2026. The operation is currently active.

Also tracked as: the gentlemen.

Timeline of this disclosure

May 15, 2026Instituut voor de Nederlandse listed by thegentlemenon the group's public leak site

Sector and geography

This disclosure adds to ransomware activity in the Public Sector sector, which has 259 disclosures indexed across all operators we track. Geographically, Instituut voor de Nederlandse is reported in NL, a country with 24 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

Instituut voor de Nederlandse Taal

listed as Instituut voor de Nederlandse · Claimed by thegentlemen · listed 6 days ago

Age

since listed · data leaked

Status timeline

Listed
May 15, 2026
Data leaked

At a glance

Group: thegentlemen
Status: Data leaked
Country: NL
Sector: Public Sector
Listed on leak site: May 15, 2026

About the victim

AI dossier — public-source company profile

Instituut voor de Nederlandse Taal (INT) is the Dutch national knowledge institute for the Dutch language, based in the Netherlands. It conducts scientific research covering vocabulary, grammar, and language variation, and curates authoritative reference works such as the Algemene Nederlandse Spraakkunst. It provides open-access digital tools and resources for scholars, educators, and the general public worldwide.

Industry: Language Research & Linguistics

Attack summary

Severity: high — The institute confirmed the attack, took all systems offline, and filed a mandatory breach notification with the Dutch Data Protection Authority, implying personal data was likely compromised. The 'data_published' status indicates exfiltration and release of data. While the institute states damage appears limited, the regulatory notification and confirmed exfiltration elevate this to high severity.

The group 'thegentlemen' claims responsibility for a hack on INT that began on 5 May 2026, causing the institute to take all systems offline; the institute has confirmed the attack and filed a report with the Dutch Data Protection Authority (Autoriteit Persoonsgegevens), indicating potential data exposure. The status is listed as 'data_published', suggesting the group claims to have exfiltrated and published data.

high

Data the group says was taken

AI dossier — extracted from the leak post

Internal organisational data
Personal data (reported to Autoriteit Persoonsgegevens)
Research and linguistic resources
Email and communications data

What the group claims

ivdnt.org rocketreach.co/instituut-voor-de-nederlandse-taal-profile_b45f686efc6979e6 It advances the study and preservation of Dutch through cutting-edge research, digital tools, and open-access resources covering vocabulary, grammar, dialects, and terminology. The institute curates authoritative references like the Algemene Nederlandse Spraakkunst for scholars, educators, and language enthusiasts worldwide

Sources

Victim siteivdnt.org

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.