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, 2025Colorado Health Network Inc listed by cephaluson the group's public leak site

Sector and geography

This disclosure adds to ransomware activity in the Healthcare sector, which has 1,779 disclosures indexed across all operators we track. Geographically, Colorado Health Network Inc is reported in United States, a country with 7,392 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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Colorado Health Network Inc

Claimed by cephalus · listed 9 months ago

Age

since listed · data leaked

Status timeline

Listed
Aug 28, 2025
Data leaked

At a glance

Group: cephalus
Status: Data leaked
Country: United States
Sector: Healthcare
Listed on leak site: Aug 28, 2025

About the victim

AI dossier — public-source company profile

Colorado Health Network (CHN), founded in 1983, is Colorado's oldest and largest provider of services and programs for people living with or impacted by HIV. The organization offers integrative medical, oral health, behavioral health, prevention, and social support services across multiple locations throughout Colorado including Denver, Fort Collins, Greeley, Colorado Springs, Pueblo, and Grand Junction. CHN serves clients regardless of ability to pay and operates both in-person and via telehealth.

Industry: HIV & Sexual Health Services / Community Health
Address: 6260 East Colfax Ave, Denver, CO 80220
Founded: 1983

Attack summary

Severity: critical — Colorado Health Network serves a highly vulnerable population of HIV-positive individuals and those with STIs. A 900 GB exfiltration from a healthcare nonprofit of this nature almost certainly includes regulated medical data (HIPAA-protected PHI), HIV status, behavioral health records, and PII at scale — all categories of maximally sensitive information. Exposure of HIV status in particular carries severe stigma and legal implications.

The ransomware group Cephalus claims to have exfiltrated over 900 GB of data from Colorado Health Network and has indicated the data will be published imminently. The disclosure status is marked as data_published, suggesting exfiltration of sensitive organizational data is confirmed or in progress.

critical

Data the group says was taken

AI dossier — extracted from the leak post

Patient medical records
HIV/STI health status information
Behavioral health records
Dental health records
Personal identifying information (PII)
Financial assistance records
Housing and social support case files
Medication access records
Insurance information
Staff/personnel data

What the group claims

900G+ data coming soon

Sources

Victim sitecoloradohealthnetwork.org

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.