MalwareHealthcareProfessional ServicesHealthcareRansomwareCapture Stored DataData ExfiltratedData EncryptedCustomer Data InvolvedIdentity (basic)Government IDMediumContained

Horizon Healthcare RCM

bd_24c4025ca3ca22ff · schema v1 · pii pii-v1

Severity

Medium

Discovered

Oct 30, 2025

Filed

Nov 26, 2025

To disclose

27 days

Affected

11state residents only

Linked

4 filings

Confidence

66%

Full breach record for Horizon Healthcare RCM →2 incidents on file

Horizon Healthcare RCM, a revenue-cycle management provider, reported a supplemental data breach affecting 11 Maine residents. The incident, occurring Dec 26-27, 2024, involved a computer virus encrypting files and unauthorized copying of patient data (names and government identifiers). Notices were sent Nov 26, 2025, offering 12 months of Kroll identity monitoring.

J jump to incidentP pin to compareR raw source

Maine clockDiscovered Oct 30, 2025 → Filed with AG Nov 26, 202527d ✓ ME AG ≤30d27 days discovery → filing

⚠ AG web formThe discovery date came from the AG web-form field, which is systematically later than the detection date stated in the letter. Treat the clock as indicative.

Incident timeline

undetected · 308 days

discovery → filing · 27 days

Dec 26, 2024

Begins

Oct 30, 2025

Discovered

Nov 26, 2025

Filed

vs. sector median

8 wks faster

This filing is one of 4 about the same incident.View merged incident

Linked disclosures

Why this link?

Regulatory filings (3) · sorted by filing gap

Vermont State AGbd_00ff9a47dfc272c42025-11-26Verified
Montana State AGbd_c5493de054e7d7522025-11-26Candidate
New Hampshire State AGbd_ef67249e664d42272025-11-26Verified

Name: Horizon Healthcare RCM
norm: horizon healthcare rcm

Name: Horizon Healthcare RCM
norm: horizon healthcare rcm
Industry: HealthcarellmProfessional Servicesllm

Discovered: Oct 30, 2025
Breach occurred: Dec 26, 2024 – Dec 27, 2024
Undetected for: 308 daysoccurrence → discovery
Materiality determined: —
Notification sent: Nov 26, 2025
Affected individuals: 11state-resident count only
Data types: Identity (basic)Government ID
Attack vector: Ransomware
MITRE ATT&CK: T1486 Data Encrypted for ImpactT1041 Exfiltration Over C2 Channel
Threat actor: ExternalFinancial

During the incident: Securely restored systems
Arranged for the party responsible to delete the copied information
Provided notice of this event to individuals
Provided free resources and guidance
Implemented additional technical measures and processes to further enhance the company’s security
Secured the services of Kroll to provide identity monitoring
Changes made: Implemented additional technical measures and processes to further enhance the company’s security
Source: Quoted from the filing itself, not independently verified.

Time to disclose: 27 days(27 days from discovery to filing)
Compliance flags: ME AG ≤30d · 27d
Discovery-date grounding: AG web formThe discovery date came from the AG web-form field, which is systematically later than the detection date stated in the letter. Treat the clock as indicative.
Clock breakdown: Statute Window Elapsed Threshold Status
Maine
Discovered: Oct 30, 2025
→ Filed with AG: Nov 26, 2025
27d 30 days ME AG ≤30d

Statute	Window	Elapsed	Threshold	Status
Maine	Discovered: Oct 30, 2025 → Filed with AG: Nov 26, 2025	27d	30 days	ME AG ≤30d

Status: No extraction artifact recorded for this disclosure.

Filing propagation · 4 filings · 4 states

View merged incident ↗

Vermont State AGNov 26 · first

Montana State AGNov 26 · first

New Hampshire State AGNov 26 · first

Maine State AGNov 26 · first · this page

Evidence ladder

Leak-site claim

Attacker assertion only. Establishes: claim date, group, alleged victim.

Press / market report

Unlocks: incident narrative, operational impact. Still no compliance clock.

State AG / regulator filingThis record

Unlocks: discovery date, data types, affected count, compliance clock.

SEC 8-K / victim statement

Unlocks: materiality, stated response, full audit trail. Ceiling removed.

Source URL: https://www.maine.gov/agviewer/content/ag/985235c7-cb95-4be2-8792-a1252b4f8318/544d5cbf-84ea-40d4-a7fe-3f4255138b2c.html
DisclosureLens links to the originating regulator URL — full filing bodies are not redistributed from public surfaces (§4.5).
Filed at: Nov 26, 2025
Raw hash: 72213132f4ab80cff04404772cad5720d89c8b8f74b078fec0c5a8978d1b88d5

Linked disclosures

Regulatory filings (3) · sorted by filing gap

Reporting entityHorizon Healthcare RCM

Victim entityHorizon Healthcare RCM

Incidentdiscovered Oct 30, 2025

Stated responseSecurely restored systems

ComplianceME AG ≤30d

Extraction provenanceno artifact recorded

Source provenancewww.maine.gov