HackingFinancial ServicesFinanceStolen CredentialsCustomer Data InvolvedFinancial accountIdentity (basic)Government IDPCIMediumContained

Bison State Bank

bd_add33ee7a75f7c68 · schema v1 · pii pii-v1

Severity

Medium

Discovered

—

Filed

Jan 31, 2026

To disclose

—

Affected

5state residents only

Linked

3 filings

Confidence

66%

Full breach record for Bison State Bank →

Bison State Bank disclosed that an unauthorized actor accessed a single employee email account between April 17, 2025, and June 30, 2025. The account contained personal information including full names and other variable data elements. The bank secured the network, engaged external cybersecurity professionals, and conducted a data review. Affected individuals are offered credit monitoring services.

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Incident timeline

Apr 17, 2025

Begins

Jan 31, 2026

Filed

This filing is one of 3 about the same incident.View merged incident

Linked disclosures

Why this link?

Regulatory filings (2) · sorted by filing gap

Nebraska State AGbd_42961be50ed4c80f2026-01-26 · +5dVerified
New Hampshire State AGbd_d61fffe9af8336282026-02-09 · +9dCandidate

Name: Bison State Bank
norm: bison state bank

Name: Bison State Bank
norm: bison state bank
Industry: Financial Servicesllm

Discovered: —
Breach occurred: Apr 17, 2025 – Jun 30, 2025
Materiality determined: —
Notification sent: Jan 26, 2026
Affected individuals: 5state-resident count only
Data types: Financial accountIdentity (basic)Government IDPCI
Attack vector: Unauthorized Access
MITRE ATT&CK: T1078 Valid AccountsT1114 Email Collection
Threat actor: External
Initial access: valid_credentials

During the incident: Secured our network
Commenced a prompt and thorough investigation
Worked very closely with external cybersecurity professionals experienced in handling these types of incidents
Conducted a thorough review of the potentially impacted data
Set up a dedicated and confidential toll-free response line
Changes made: Providing complimentary credit monitoring and identity theft protection services through IDX
Continually evaluate and modify our practices and internal controls to enhance the security and privacy of your personal information
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.

Filing propagation · 3 filings · 3 states

View merged incident ↗

Nebraska State AGJan 26 · first

Massachusetts State AG+5d · this page

New Hampshire State AG+14d

Pattern: first filing Jan 26 (NE), last Feb 9 (NH) — a 14-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://www.mass.gov/doc/2026-146-bison-state-bank/download
DisclosureLens links to the originating regulator URL — full filing bodies are not redistributed from public surfaces (§4.5).
Filed at: Jan 31, 2026
Raw hash: 84c0a5afaa2a1630a953674e36a3c8fd854738da0c1666ff0a3ab938f6c57768

Linked disclosures

Regulatory filings (2) · sorted by filing gap

Reporting entityBison State Bank

Victim entityBison State Bank

IncidentUnauthorized Access

Stated responseSecured our network

Complianceclock not assessable

Extraction provenanceno artifact recorded

Source provenancewww.mass.gov