Social EngineeringFinancial ServicesFinancePhishingStolen CredentialsCustomer Data InvolvedPIIIdentity (basic)Financial accountLowResolved

CNB Bank & Trust, N.A.

bd_529677af1311f623 · schema v1 · pii pii-v1

Severity

Low

Discovered

Apr 17, 2023

Filed

May 17, 2023

To disclose

4 weeks

Affected

3state residents only

Confidence

64%

Full breach record for CNB Bank & Trust, N.A. →2 incidents on file

CNB Bank & Trust, N.A. notified Montana residents of a data security incident involving unauthorized access to an employee's email account between September 30 and November 7, 2022. The bank determined on April 17, 2023, that some customers' personal and financial information was accessed. The bank offered one year of credit monitoring and implemented additional security measures.

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Incident timeline

undetected · 199 days

discovery → filing · 4 weeks / 30 days

Sep 30, 2022

Begins

Apr 17, 2023

Discovered

May 17, 2023

Filed

vs. sector median

5 wks faster

Tracked as a single-filing incident — the only disclosure on record for this event so far.Confirmed3 affectedView incident

Name: CNB Bank & Trust, N.A.
norm: cnb bank trust na

Name: CNB Bank & Trust, N.A.
norm: cnb bank trust na
Industry: Financial Servicesllm

Discovered: Apr 17, 2023
Breach occurred: Sep 30, 2022 – Nov 7, 2022
Undetected for: 199 daysoccurrence → discovery
Materiality determined: —
Notification sent: May 17, 2023
Affected individuals: 3state-resident count only
Data types: PIIIdentity (basic)Financial account
Attack vector: Phishing
MITRE ATT&CK: T1566.002 Spearphishing LinkT1078 Valid AccountsT1114 Email Collection
Threat actor: ExternalFinancial
Initial access: phishing_link

During the incident: Secured the account
Launched an investigation
Completed a thorough review of the contents of the involved email account
Offering a free one-year membership to Equifax CompleteTM Premier credit and identity monitoring
Changes made: Implemented additional safeguards and technical security measures
Will continue to train our employees concerning data security
Source: Quoted from the filing itself, not independently verified.

Time to disclose: 4 weeks(30 days from discovery to filing)
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://dojmt.gov/wp-content/uploads/OCP/Consumer-notification-letter-290.pdf
DisclosureLens links to the originating regulator URL — full filing bodies are not redistributed from public surfaces (§4.5).
Filed at: May 17, 2023
Raw hash: 03ae7e21e7482331ff37bfddb2735acb8948d15f674012dee80e270f25b222e5

Reporting entityCNB Bank & Trust, N.A.

Victim entityCNB Bank & Trust, N.A.

Incidentdiscovered Apr 17, 2023

Stated responseSecured the account

Complianceclock not assessable

Extraction provenanceno artifact recorded

Source provenancedojmt.gov