Disclosure context

About insomnia

Based on the limited publicly available information, Insomnia is a relatively new ransomware group that first emerged in February 2026, appearing to be financially motivated based on their targeting patterns and operational behavior. The group's country of origin and potential affiliations with other ransomware operations remain unknown, with insufficient public documentation from major threat intelligence sources to determine whether they operate as a Ransomware-as-a-Service model or as an independent entity. Their attack methodology and specific technical capabilities have not been extensively documented by CISA, FBI, or major security research firms, though their targeting of 29 known victims across healthcare, technology, manufacturing, and hospitality sectors in the United States, Singapore, and Brazil suggests a broad opportunistic approach rather than highly selective operations. Given the group's recent emergence and limited public reporting from established threat intelligence sources, there are no widely documented notable campaigns or high-profile incidents that have garnered significant attention from law enforcement or major security vendors. As of current reporting, the operational status of Insomnia remains unclear due to the lack of comprehensive public analysis from authoritative sources, making it difficult to assess whether the group remains active or has ceased operations. The group has been linked to 34 public disclosures across our corpus. First observed on a leak site on February 7, 2026; most recent post April 28, 2026. The operation is currently active.

Timeline of this disclosure

April 9, 2026United Medical Doctors listed by insomniaon 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, United Medical Doctors is reported in US, a country with 2,713 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

← All victims

United Medical Doctors

Claimed by insomnia · listed 1 month ago

41d

Age

since listed · data leaked

Status timeline

Listed
Apr 9, 2026
Data leaked

At a glance

Group: insomnia
Status: Data leaked
Country: US
Sector: Healthcare
Listed on leak site: Apr 9, 2026

About the victim

AI dossier — public-source company profile

United Medical Doctors (UMD) is an independent multi-specialty medical and surgical group operating 80+ locations across four Southern California counties (Riverside, Orange, San Diego, and Los Angeles). The group offers 50+ specialties, 250+ providers, ambulatory surgery centers, clinical research facilities, and its own nursing college. It is described as one of the largest integrated private practices in California.

Industry: Multi-Specialty Outpatient Medical & Surgical Group
Address: Murrieta, California, USA
Employees: 201-500

Attack summary

Severity: critical — UMD is a large multi-specialty healthcare provider with 250+ providers and 80+ locations serving a broad patient population; a data_published status implies confirmed exfiltration and public release of data likely containing protected health information (PHI) and PII at scale, which constitutes regulated sensitive medical data under HIPAA.

The Insomnia ransomware group listed United Medical Doctors with a disclosed status of data_published, indicating exfiltration and/or publication of company data. No ransom amount or specific data size was stated in the post.

critical

Data the group says was taken

AI dossier — extracted from the leak post

Patient medical records
Clinical research data
Provider and staff information
Insurance and billing records
Surgical and outpatient care records
Administrative and operational data

What the group claims

United Medical Doctors (UMD) is an independent multi‑specialty medical‑surgical group with 70+ Southern California locations and 40+ specialties. They focus on high‑quality, compassionate care, patient satisfaction, process improvement, outpatient surgery, clinical research.

The leak post

captured from the group's site

Insomnia Human Verification What is 1 + 1 = ? Submit Nephrology Associates Hospitals &amp; Physicians Clinics Nephrology Associates, PA is a leading central Arkansas nephrology practice with seven highly trained physicians across seven locations. They provide compassionate kidney care, accept all insurances, and aim to create a welcoming environment for patients. Website: www.arnapa.com Revenue: $5 million Employees: 11-50 Location: Little Rock, Arkansas, USA Notified: 2026-4-6 METO Systems Industrial Machinery &amp; Equipment METO Systems designs and manufactures stainless-steel industrial material‑handling equipment for regulated industries. Products include lifts, blenders, transporters, and docking systems, they offer installation, training, customization, and support. Website: www.metosystems.com Revenue: $6 million Employees: 11-50 Location: Parsippany, New Jersey, USA Notified: 2026-3-31 United Medical Doctors Hospitals &amp; Physicians Clinics United Medical Doctors (UMD) is an independent multi‑specialty medical‑surgical group with 70+ Southern California locations and 40+ specialties. They focus on high‑quality, compassionate care, patient satisfaction, process improvemen…

Screenshot of the leak post

Leak screenshot for United Medical Doctors

Sources

Victim sitewww.unitedmd.com
Leak posthttp://i62huw7ve22rpyw6lnq3kmfump2dmsg4xpveec3ere73njwatrz74gad.onion/Company/UnitedMD/

Source

Indexed 1 month 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.