Was Thialf hit by ransomware?

Thialf was listed by the thegentlemen ransomware operation (Netherlands), 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 Thialf breach?

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

Ransomware victim disclosure

← All victims

Thialf

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: Netherlands
Sector: Energy & Utilities
Listed on leak site: Jul 23, 2026

About the victim

AI dossier — public-source company profile

Thialf is a world-renowned ice arena in Heerenveen, Netherlands, serving as the home base for the Dutch national speed skating team. It hosts elite competitions in long-track and short-track speed skating, figure skating, and ice hockey, and has been confirmed as the long-track speed skating venue for the 2030 Winter Olympics. The facility also offers public recreational skating and corporate event services.

Industry: Sports & Recreation Facilities
Address: Heerenveen, Netherlands

Attack summary

Severity: low — The leak post contains only general description of the company with no evidence of data exfiltration, proof files, or operational impact. No ransom demand or specific data types are mentioned. This appears to be a listing/announcement without substantive proof.

The group claims to have conducted an attack on Thialf, with the leak post published on a data disclosure platform. No specific details are provided regarding what data was exfiltrated or whether encryption occurred.

low

What the group claims

***.nl zoominfo.com/c/thialf/430686423 Thialf is a world-renowned ice arena located in Heerenveen, Netherlands, often referred to as the "Cathedral of Speed Skating." It serves as the home base for the Dutch national speed skating team and hosts a wide range of ice sports, including long track and short track speed skating, figure skating, and ice hockey. Recently, it was officially confirmed as the long-track speed skating venue for the 2030 Winter Olympics. The facility is celebrated for its modern, sustainable design and its role as a major hub for both elite professional competitions and public recreational skating.

Sources

Victim sitethialf.nl

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.

Is this your supplier? Your competitor? You?

Pro plans monitor your domain, corporate emails, and crypto wallets across every new ransomware leak-site post, breach dump and Telegram callout — alerts within 5 minutes.

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, 2026Thialf 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 Energy & Utilities sector, which has 166 disclosures indexed across all operators we track. Geographically, Thialf is reported in Netherlands, a country with 42 ransomware disclosures in our corpus.

If your organisation is affected

A listing by thegentlemen means Thialf 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, NCSC-NL (Netherlands), 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.