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 26, 2025Town of Vienna, VA listed by cephaluson the group's public leak site

Sector and geography

This disclosure adds to ransomware activity in the Public Sector sector, which has 259 disclosures indexed across all operators we track. Geographically, Town of Vienna, VA 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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Town of Vienna, VA

Claimed by cephalus · listed 9 months ago

Age

since listed · data leaked

Status timeline

Listed
Aug 26, 2025
Data leaked

At a glance

Group: cephalus
Status: Data leaked
Country: United States
Sector: Public Sector
Listed on leak site: Aug 26, 2025

About the victim

AI dossier — public-source company profile

The Town of Vienna is a incorporated municipality in Fairfax County, Virginia, United States. It provides local government services including public safety, public works, parks and recreation, and community development to approximately 16,000 residents. The town operates under a council-manager form of government and maintains its official web presence at viennava.gov.

Industry: Municipal Government
Address: 127 Center Street South, Vienna, VA 22180, United States
Employees: 51-200
Founded: 1890

Attack summary

Severity: high — The victim is a municipal government entity whose systems likely contain PII of residents and employees, financial records, and public safety data. The 'data_published' disclosure status indicates data was or is being released, which elevates severity; however, the lack of specific data categories or confirmed volume prevents a 'critical' rating.

The ransomware group cephalus claims an attack on the Town of Vienna, VA, with the leak post indicating data publication is forthcoming ('coming soon'); no specific details on encryption, exfiltration methods, or data categories have been disclosed in the truncated post.

high

Data the group says was taken

AI dossier — extracted from the leak post

Municipal government records
Resident personal information
Employee records
Financial records
Public safety data

What the group claims

coming soon

Sources

Victim siteviennava.gov

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.