HackingHealthcareHealthcareStolen CredentialsData ExfiltratedCustomer Data InvolvedFinancial accountHealth (basic)Identity (basic)Government IDPHIMediumContained

Mountrail County Medical Center

bd_670385ef82197513 · schema v1 · pii pii-v2

Severity

Medium

Discovered

May 26, 2026

Filed

Oct 1, 2026

To disclose

—

Affected

5state residents only

Confidence

68%

Full breach record for Mountrail County Medical Center →2 incidents on file

Aesto, LLC, a healthcare data archiving provider, disclosed a cyber incident affecting Mountrail County Medical Center. Unauthorized access occurred between Dec 2-18, 2025, impacting a limited portion of AWS infrastructure. Protected health information (names, DOB, SSN, driver's license, financial accounts) of some individuals was accessed. Aesto engaged GuidePoint Security for forensic investigation, contained the breach by Dec 18, 2025, and notified affected entities on June 26, 2026.

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Incident timeline

undetected · 175 days

Dec 2, 2025

Begins

May 26, 2026

Discovered

Oct 1, 2026

Filed

Tracked as a single-filing incident — the only disclosure on record for this event so far.Confirmed5 affectedView incident

Name: Aesto Health
norm: aesto health
Domain: aestohealth.com

Name: Mountrail County Medical Center
norm: mountrail county medical center
Industry: Healthcarellm

Discovered: May 26, 2026
Breach occurred: Dec 2, 2025 – Dec 18, 2025
Undetected for: 175 daysoccurrence → discovery
Materiality determined: —
Notification sent: Jun 26, 2026
Affected individuals: 5state-resident count only
Data types: Financial accountHealth (basic)Identity (basic)Government IDPHI
Attack vector: Unauthorized Access
MITRE ATT&CK: T1190 Exploit Public-Facing ApplicationT1078 Valid Accounts
Threat actor: External
Regulator citations: Offered to notify HHS OCR on behalf of Covered Entities
Initial access: exploit_public_facing

During the incident: Engaged GuidePoint Security, LLC to perform Incident Response services
Reset credentials
Enhanced security measures and monitoring tools
Reviewed existing policies and training protocols
Closed the security gaps exploited by the threat actor
Deleted impacted Lambda functions
Rotated all impacted AWS secrets
Deleted unauthorized files uploaded by the threat actor
Changes made: Hardened network security
Implemented continuous monitoring of the network
Source: Quoted from the filing itself, not independently verified.

Compliance flags: — (clock not assessable for this source)

Status: No extraction artifact recorded for this disclosure.

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.mass.gov/doc/2026-1782-mountrail-county-medical-center/download
DisclosureLens links to the originating regulator URL — full filing bodies are not redistributed from public surfaces (§4.5).
Filed at: Oct 1, 2026
Raw hash: aa63dd4bdd9d2543b648ac7c7d3a5a1e76dd3b41918d8d22f16cdb9593efecb0

Reporting entityAesto Health

Victim entityMountrail County Medical Center

Incidentdiscovered May 26, 2026

Stated responseEngaged GuidePoint Security, LLC to perform Incident Response services

Complianceclock not assessable

Extraction provenanceno artifact recorded

Source provenancewww.mass.gov