Was Avalon Hills hit by ransomware?

Avalon Hills was listed by the sinobi ransomware operation (United States), 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 sinobi ransomware group?

sinobi 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 Avalon Hills breach?

sinobi published data attributed to Avalon Hills. Darkfield captured the leak post and a screenshot of the listing.

Ransomware victim disclosure

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Avalon Hills

Claimed by Sinobi · listed 5 months ago

Age

since listed · data leaked

Status timeline

ListedJan 19, 2026
Data leakeddate unknown

At a glance

Group: Sinobi
Status: Data leaked
Country: United States
Listed on leak site: Jan 19, 2026

About the victim

AI dossier — public-source company profile

Avalon Hills is a residential eating disorder treatment program that provides care to patients using traditional psychotherapies and applied neuroscience, including research on human brain plasticity. The program supports clients and their families with clinical treatment, financial/insurance coordination, and logistical services. It appears to operate as a dedicated inpatient or residential facility serving individuals with serious eating disorders.

Industry: Eating Disorder Treatment & Behavioral Health
Employees: 51-200

Attack summary

Severity: critical — Avalon Hills is a medical/behavioral health facility treating patients with eating disorders. The exfiltrated data almost certainly includes protected health information (PHI) regulated under HIPAA, financial records, and sensitive patient and family data at a vulnerable population scale. Data has been confirmed published, making this a critical disclosure.

The ransomware group Sinobi claims to have exfiltrated data from Avalon Hills and has published the data (disclosed_status: data_published). The leaked post references financial records, insurance/utilization review information, and patient-related content consistent with a behavioral health treatment facility.

critical

Data the group says was taken

AI dossier — extracted from the leak post

Patient treatment records
Financial records
Insurance and utilization review data
Family contact and travel information
Staff and administrative records

What the group claims

The Avalon Hills business staff work behind the scenes to help manage all aspects of the program. They route calls, assist with travel plans for clients and families, track all things financial, keep all of the technical machines purring and whatever else it takes to keep a busy program in business! The financial office and utilization review team partners with families to help them access and maximize their insurance benefits. This requires the dedication of families to expand the financial resources available to them for treatment. We help those struggling with an eating disorder recover through a combination of the best, tried-and-true traditional psychotherapies and applied neuroscience, including the latest discoveries about human brain plasticity. Prior to arriving at Avalon Hills, our 21 year-old daughter struggled with a life-threatening eating disorder for over 4 years.

Sources

Leak posthttp://sinobi6ftrg27d6g4sjdt65malds6cfptlnjyw52rskakqjda6uvb7yd.onion/leaks/696d44836387a4c9a26e8ec4

Source

Indexed 5 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.

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Disclosure context

About sinobi

Based on the limited publicly available information, Sinobi appears to be a recently emerged ransomware operation first observed in July 2025, with financial motivations evidenced by their targeting of 268 victims across multiple sectors. The group's origin and specific affiliations remain undocumented in public threat intelligence reporting, and there is no confirmed information regarding whether they operate as a Ransomware-as-a-Service model or as an independent entity. Their attack methodology and technical capabilities have not been extensively documented by major security research organizations, though their targeting patterns suggest a broad opportunistic approach rather than highly selective operations. The group demonstrates a preference for targeting organizations in the United States, India, United Kingdom, Canada, and Italy, with a focus on manufacturing, healthcare, construction, and technology sectors, suggesting they may exploit common vulnerabilities across these industries rather than deploying sophisticated, sector-specific attack vectors. No major high-profile campaigns or significant law enforcement actions against Sinobi have been publicly reported by CISA, FBI, or established threat intelligence firms. Given the recent emergence timeline and lack of extensive public documentation, the group's current operational status and long-term trajectory remain unclear, though the substantial victim count suggests continued activity as of the last available reporting period. The group has been linked to 274 public disclosures across our corpus. First observed on a leak site on July 5, 2025; most recent post May 8, 2026. The operation is currently active.

Timeline of this disclosure

January 19, 2026Avalon Hills listed by sinobion the group's public leak site

Other recent disclosures by sinobi

sinobi has been linked to 274 public victims on Darkfield. A sample of the most recent:

See the full sinobi dossier →

Sector and geography

Geographically, Avalon Hills is reported in United States, a country with 7,392 ransomware disclosures in our corpus.

If your organisation is affected

A listing by sinobi means Avalon Hills 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.
Monitor for the data appearing on sinobi'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.