Disclosure context

About cephalus

Based on available public information, Cephalus is a recently emerged ransomware group first observed in August 2025, operating with apparent financial motivations targeting organizations primarily across the United States, United Kingdom, Netherlands, and Ireland. The group has claimed 19 victims since emergence, with no publicly documented country of origin or confirmed affiliations to established ransomware families or RaaS operations by major security researchers or government agencies. Their attack methodology and specific technical capabilities remain largely undocumented in public threat intelligence reporting, though their targeting pattern shows focus on healthcare, business services, financial services, and manufacturing sectors alongside organizations of undetermined industry classification. No major high-profile campaigns, record ransom demands, or law enforcement disruption actions have been publicly reported by CISA, FBI, or established security research firms at this time. The group appears to remain active as of current reporting, though the limited public documentation suggests either highly targeted operations or insufficient analysis coverage by major threat intelligence organizations. The group has been linked to 19 public disclosures across our corpus. First observed on a leak site on August 26, 2025; most recent post August 29, 2025. The operation is currently inactive.

Timeline of this disclosure

August 28, 2025CoCo Yachts listed by cephaluson the group's public leak site

Data size: 1.8 TB

Sector and geography

This disclosure adds to ransomware activity in the Manufacturing sector, which has 2,458 disclosures indexed across all operators we track. Geographically, CoCo Yachts is reported in Netherlands, a country with 54 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

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CoCo Yachts

Claimed by cephalus · listed 9 months ago

1.8 TB

Data size

Age

since listed · data leaked

Status timeline

Listed
Aug 28, 2025
Data leaked

At a glance

Group: cephalus
Status: Data leaked
Country: Netherlands
Sector: Manufacturing
Listed on leak site: Aug 28, 2025
Data size: 1.8 TB

About the victim

AI dossier — public-source company profile

CoCo Yachts B.V. is a Dutch maritime design company headquartered in Gorinchem, Netherlands, founded in November 2011. The company specialises in the design of innovative aluminium vessels including high-speed passenger ferries, patrol boats, hybrid survey vessels, and yachts. It operates internationally, with construction partners in India, China, and elsewhere, and has received recognition such as Ship of the Year 2024 for its fully electric ferry designs.

Industry: Naval & Maritime Vessel Design
Address: Edisonweg 21e, 4207 HE Gorinchem, Netherlands
Employees: 11-50
Founded: 2011

Attack summary

Severity: critical — The exfiltration of 1.8 TB includes claimed naval/military ship design data (a country's naval vessel designs), which constitutes sensitive defence-related intellectual property, alongside PII (employee and client data). The combination of potential national-security-relevant design data and large-scale personal/business data warrants a critical classification.

The group 'cephalus' claims to have exfiltrated 1.8 TB of data from CoCo Yachts, including project files, client information, employee records, and purportedly naval ship design data attributed to an unspecified country. The group states a data download link is forthcoming.

critical

Data the group says was taken

AI dossier — extracted from the leak post

Project files
Client information
Employee information
Naval ship design data

What the group claims

We got a total of 1.8TB+ of data,including project,clients,employee information,and a certain country's naval ship design..... The data link will coming soon

Sources

Victim sitewww.cocoyachts.com

Source

Indexed 9 months 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.