Was MAMMUT.COM hit by ransomware?

MAMMUT.COM was listed by the clop ransomware operation (Switzerland), 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 clop ransomware group?

clop 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 MAMMUT.COM breach?

clop published data attributed to MAMMUT.COM. Darkfield captured the leak post and a screenshot of the listing.

Ransomware victim disclosure

← All victims

MAMMUT.COM

Claimed by Clop · listed 5 days ago

Age

since listed · data leaked

Status timeline

ListedAug 12, 2026
Data leakeddate unknown

At a glance

Group: Clop
Status: Data leaked
Country: Switzerland
Sector: Retail & E-Commerce
Listed on leak site: Aug 12, 2026

About the victim

AI dossier — public-source company profile

Mammut is a Swiss retailer specializing in high-performance outdoor and mountaineering equipment, including clothing, footwear, backpacks, climbing gear, and avalanche safety equipment. The company operates an e-commerce platform (mammut.com) serving European customers with free shipping over €100.

Industry: Sporting Goods & Outdoor Equipment

Attack summary

Severity: low — The disclosed post contains no proof files, screenshots, data samples, or specific claims about exfiltrated or encrypted data. Only a generic placeholder message is present, indicating announcement-only without operational impact or evidence.

The leak post provides no substantive information about the attack. It contains only a generic queue/redirect message with no details on what data was allegedly exfiltrated, encrypted, or compromised.

low

Original description

AI-summarised, not from the leak post

Mammut is a Swiss outdoor sports brand founded in 1862, headquartered in Seon, Switzerland. The company specializes in designing and manufacturing high-performance equipment, apparel, and footwear for mountaineering, climbing, skiing, and hiking. Known for its premium quality and innovation, Mammut serves professional athletes and outdoor enthusiasts worldwide, operating across retail stores and e-commerce channels globally.

The leak post

captured from the group's site

You have been placed in a queue, awaiting forwarding to the platform. 
Please do not refresh the page, you will be automatically redirected.

Sources

Victim siteMAMMUT.COM
Leak posthttp://santat7kpllt6iyvqbr7q4amdv6dzrh6paatvyrzl7ry3zm72zigf4ad.onion/

Source

Indexed 5 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 clop

Clop (also stylized as "Cl0p") is a financially motivated ransomware group and cybercriminal enterprise that emerged in early 2020 as an evolution of the earlier CryptoMix ransomware family, operating primarily for monetary extortion against large enterprise targets. The group is widely assessed by Mandiant, CISA, and other reputable researchers to have ties to Russian-speaking cybercriminal actors, with some researchers linking their operations to the broader FIN11 threat cluster; they operate a Ransomware-as-a-Service (RaaS) model while also conducting direct intrusion operations. Clop is particularly distinguished for its aggressive exploitation of zero-day and n-day vulnerabilities in managed file transfer (MFT) and enterprise software platforms as primary initial access vectors, most notably the exploitation of Accellion FTA (2020-2021), Fortra GoAnywhere MFT (CVE-2023-0669), and the MOVEit Transfer vulnerability (CVE-2023-34362) in 2023, and consistently employs double extortion tactics — exfiltrating sensitive data prior to or in lieu of encryption and threatening public disclosure on their dedicated leak site to coerce payment. Clop has been responsible for some of the most impactful ransomware campaigns on record, with their 2023 MOVEit exploitation campaign alone affecting over 1,000 organizations globally and impacting entities including Shell, the U.S. Department of Energy, British Airways, and numerous U.S. federal agencies, with the broader campaign representing one of the largest mass-exploitation events in ransomware history; Ukrainian law enforcement arrested six individuals linked to Clop operations in June 2021, though the group's core leadership is assessed to remain outside of effective law enforcement jurisdiction. As of the most recent publicly available intelligence, Clop remains active, continuing to leverage vulnerability exploitation campaigns against enterprise file transfer solutions and maintaining a victim count exceeding 1,250 known organizations, with consistent targeting concentrated in the United States, Canada, United Kingdom, Australia, and Germany across technology, business services, manufacturing, and consumer services sectors. The group has been linked to 1,343 public disclosures across our corpus. First observed on a leak site on March 13, 2020; most recent post August 14, 2026. The operation is currently active.

Also tracked as: Cl0p.

Timeline of this disclosure

August 12, 2026MAMMUT.COM listed by clopon the group's public leak site

Other recent disclosures by clop

clop has been linked to 1,343 public victims on Darkfield. A sample of the most recent:

See the full clop dossier →

Sector and geography

This disclosure adds to ransomware activity in the Retail & E-Commerce sector, which has 18 disclosures indexed across all operators we track. Geographically, MAMMUT.COM is reported in Switzerland, a country with 39 ransomware disclosures in our corpus.

If your organisation is affected

A listing by clop means MAMMUT.COM 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-CH (Switzerland), as required for your jurisdiction.
Monitor for the data appearing on clop'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.