MalwareHealthcareFinancial ServicesHealthcareRansomwareData ExfiltratedData EncryptedCustomer Data InvolvedIdentity (basic)Government IDMediumContained

Horizon Healthcare RCM

bd_b9ed9343a285ba77 · schema v1 · pii pii-v1

Severity

Medium

Discovered

May 20, 2025

Filed

Jun 27, 2025

To disclose

5 weeks

Affected

6state residents only

Linked

8 filings

Confidence

66%

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

Horizon Healthcare RCM reported a cybersecurity incident to the Maine Attorney General affecting 6 Maine residents. The breach occurred on December 26-27, 2024, when a computer virus locked access to files (ransomware) and files were copied without permission. The breach was discovered on May 20, 2025, after an intensive review. Affected data included names and Social Security numbers. Horizon notified federal law enforcement, implemented additional safeguards, and provided 12 months of credit monitoring through Kroll to affected individuals.

J jump to incidentP pin to compareR raw source

Maine clockDiscovered May 20, 2025 → Filed with AG Jun 27, 202538d ⏱ ME AG >30d5 weeks 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 · 145 days

discovery → filing · 5 weeks / 38 days

Dec 26, 2024

Begins

May 20, 2025

Discovered

Jun 27, 2025

Filed

vs. sector median

7 wks faster

This filing is one of 8 about the same incident.View merged incident

Linked disclosures

Why this link?

Regulatory filings (7) · sorted by filing gap

HHS OCRbd_2494d37011c4c79c2025-06-27Verified
Indiana State AGbd_25fcf4be90ea13492025-06-27Verified
South Carolina State AGbd_2c30bdb47fb3604a2025-06-27Verified
Nebraska State AGbd_683236bfcdb2a0902025-06-27Verified

Show 3 more filings ↓up to 4d gap

Massachusetts State AGbd_8ff54dbb0d7f4d762025-06-27Verified
New Hampshire State AGbd_a3ed180e1ba972d72025-06-27Verified
Illinois State AGbd_5a1984ac023e4ba82025-07-01 · +4dVerified

Name: Horizon Healthcare RCM
norm: horizon healthcare rcm

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

Discovered: May 20, 2025
Breach occurred: Dec 26, 2024 – Dec 27, 2024
Undetected for: 145 daysoccurrence → discovery
Materiality determined: —
Notification sent: Jun 27, 2025
Affected individuals: 6state-resident count only
Data types: Identity (basic)Government ID
Attack vector: Unknown
MITRE ATT&CK: T1486 Data Encrypted for ImpactT1041 Exfiltration Over C2 Channel
Threat actor: ExternalFinancial
Regulator citations: Notified Federal law enforcement regarding the eventProviding written notice of this incident to relevant state regulators

During the incident: Notified Federal law enforcement regarding the event
Implemented additional technological safeguards and training to its employees
Providing access to credit monitoring services for twelve (12) months, through Kroll
Providing impacted individuals with guidance on how to better protect against identity theft and fraud
Providing written notice of this incident to relevant state regulators
Providing written notice to the three major credit reporting agencies, Equifax, Experian, and TransUnion
Changes made: Implemented additional technological safeguards and training to its employees
Arranged for the party responsible for this matter to delete the copied information
Source: Quoted from the filing itself, not independently verified.

Time to disclose: 5 weeks(38 days from discovery to filing)
Compliance flags: ME AG >30d · 38d
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: May 20, 2025
→ Filed with AG: Jun 27, 2025
38d 30 days (soft) ME AG >30d

Statute	Window	Elapsed	Threshold	Status
Maine	Discovered: May 20, 2025 → Filed with AG: Jun 27, 2025	38d	30 days (soft)	ME AG >30d

Status: No extraction artifact recorded for this disclosure.

Filing propagation · 8 filings · 7 states

View merged incident ↗

HHS OCRJun 27 · first

Indiana State AGJun 27 · first

South Carolina State AGJun 27 · first

Nebraska State AGJun 27 · first

Massachusetts State AGJun 27 · first

New Hampshire State AGJun 27 · first

Maine State AGJun 27 · first · this page

Illinois State AG+4d

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-a1252b4f8318/77385ffe-5135-492d-a928-76d345819a3c.html
DisclosureLens links to the originating regulator URL — full filing bodies are not redistributed from public surfaces (§4.5).
Filed at: Jun 27, 2025
Raw hash: 19637e9e82eade12ccd028a32eb041deb54e2547a7ed4c0c42cceb50768f1816

Linked disclosures

Regulatory filings (7) · sorted by filing gap

Reporting entityHorizon Healthcare RCM

Victim entityHorizon Healthcare RCM

Incidentdiscovered May 20, 2025

Stated responseNotified Federal law enforcement regarding the event

ComplianceME AG >30d

Extraction provenanceno artifact recorded

Source provenancewww.maine.gov