MalwareFinancial ServicesFinanceRansomwareData EncryptedTargetedPIIIdentity (basic)Government IDFinancial accountMediumContained

Horicon Bank

bd_56f43a49c9b9e0ee · schema v1 · pii pii-v1

Severity

Medium

Discovered

Sep 20, 2021

Filed

Nov 15, 2021

To disclose

8 weeks

Affected

10state residents only

Linked

4 filings

Confidence

67%

Full breach record for Horicon Bank →

Horicon Bank notified Montana residents of a cybersecurity incident discovered on September 20, 2021, where an unauthorized third party gained access and encrypted internal systems. The incident involved personal information including names, account numbers, addresses, phone numbers, SSNs, and driver's license numbers. Horicon retained forensic specialists, engaged law enforcement, and offered 12 months of Experian IdentityWorks.

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Incident timeline

discovery → filing · 8 weeks / 56 days

Sep 20, 2021

Discovered

Nov 15, 2021

Filed

vs. sector median

on median

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

Maine State AGbd_10f2b758a7ee743c2021-11-16 · +1dVerified
Massachusetts State AGbd_23c8f6c3a40358792021-11-16 · +1dVerified
New Hampshire State AGbd_1137e14623fb8bef2021-11-22 · +7dVerified

Name: Horicon Bank
norm: horicon bank

Name: Horicon Bank
norm: horicon bank
Industry: Financial Servicesllm

Discovered: Sep 20, 2021
Materiality determined: —
Notification sent: —
Affected individuals: 10state-resident count only
Data types: PIIIdentity (basic)Government IDFinancial account
Data elements: Social Security number
Attack vector: Ransomware
MITRE ATT&CK: T1486 Data Encrypted for ImpactT1078 Valid Accounts
Threat actor: ExternalFinancial
Regulator citations: Reported this incident to the appropriate law enforcement authorities
Initial access: valid_credentials

During the incident: Retained forensic specialists and counsel
Reported this incident to the appropriate law enforcement authorities
Deployed further end point protection software on our systems
Reviewing our security measures
Worked with consultants to restore the affected systems
Offering a complimentary 12-month membership of Experian's IdentityWorks
Changes made: Deployed further end point protection software on our systems
Reviewing our security measures
Worked with consultants to restore the affected systems
Source: Quoted from the filing itself, not independently verified.

Time to disclose: 8 weeks(56 days from discovery to filing)
Compliance flags: — (clock not assessable for this source)

Status: No extraction artifact recorded for this disclosure.

Filing propagation · 4 filings · 4 states

View merged incident ↗

Montana State AGNov 15 · first · this page

Maine State AG+1d

Massachusetts State AG+1d

New Hampshire State AG+7d

Pattern: first filing Nov 15 (MT), last Nov 22 (NH) — a 7-day rolling notification. Rolling spreads often mean counsel is filing as thresholds trip per state. Why this link?

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://dojmt.gov/wp-content/uploads/OCP/Consumer-Notification-Letter-87.pdf
DisclosureLens links to the originating regulator URL — full filing bodies are not redistributed from public surfaces (§4.5).
Filed at: Nov 15, 2021
Raw hash: a9862fb606dbf9b6407bdca910857262686731055b89398d325c6e4527cdac31

Linked disclosures

Regulatory filings (3) · sorted by filing gap

Reporting entityHoricon Bank

Victim entityHoricon Bank

Incidentdiscovered Sep 20, 2021

Stated responseRetained forensic specialists and counsel

Complianceclock not assessable

Extraction provenanceno artifact recorded

Source provenancedojmt.gov