Was National Museum hit by ransomware?

National Museum was listed by the thegentlemen ransomware operation (Denmark), 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 National Museum breach?

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

Ransomware victim disclosure

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Nationalmuseet (National Museum of Denmark)

listed as National Museum · Claimed by Thegentlemen · listed 7 hours ago

Today

Age

since listed · data leaked

Status timeline

ListedJun 15, 2026
Data leakeddate unknown

At a glance

Group: Thegentlemen
Status: Data leaked
Country: Denmark
Sector: Public Sector
Listed on leak site: Jun 15, 2026

About the victim

AI dossier — public-source company profile

Nationalmuseet is Denmark's premier national museum located in Copenhagen, dedicated to preserving and presenting Danish cultural history and global ethnographic collections. It houses significant archaeological treasures including Viking artifacts and the Sun Chariot, and operates multiple museum locations across Denmark.

Industry: Museums & Cultural Heritage
Address: Ny Vestergade 10, Prinsens Palæ, DK-1471 København K, Denmark

Attack summary

Severity: low — The leak post contains only a generic description of the museum with no evidence of proof files, screenshots, or specifics about what data was actually compromised or published. No operational disruption is claimed.

The threat actor claims to have compromised Nationalmuseet and published data. The leak post provides no specific details on the nature of data exfiltrated, encryption status, or operational impact.

low

What the group claims

***.dk zoominfo.com/c/national-museum/372526094 The National Museum of Denmark, located in the heart of Copenhagen, is the country's premier institution for cultural history, spanning from the Stone Age to the present day. It houses world-renowned archaeological treasures—including Viking hoards, the ancient Sun Chariot, and the Egtved Girl—alongside extensive global ethnographic collections. The museum is dedicated to exploring and sharing Denmark's rich heritage and global human history through engaging, research-driven exhibitions

Sources

Victim sitenatmus.dk

Source

Indexed 7 hours 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 504 public disclosures across our corpus. First observed on a leak site on September 9, 2025; most recent post June 15, 2026. The operation is currently active.

Also tracked as: the gentlemen.

Timeline of this disclosure

June 15, 2026National Museum listed by thegentlemenon the group's public leak site

Other recent disclosures by thegentlemen

thegentlemen has been linked to 504 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 Public Sector sector, which has 466 disclosures indexed across all operators we track. Geographically, National Museum is reported in Denmark, a country with 13 ransomware disclosures in our corpus.

If your organisation is affected

A listing by thegentlemen means National Museum 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, CFCS (Denmark), 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.