HackingFinancial ServicesFinanceStolen CredentialsCustomer Data InvolvedEmployee Data InvolvedIdentity (basic)Government IDMediumContained

The Middlefield Banking Company

bd_719ea19c8e005680 · schema v1 · pii pii-v1

Severity

Medium

Discovered

Apr 12, 2023

Filed

Dec 21, 2023

To disclose

36 weeks

Affected

54state residents only

Linked

6 filings

Confidence

65%

Full breach record for The Middlefield Banking Company →2 incidents on file

Middlefield Banking Company experienced a data security incident between April 11-12, 2023, where an unauthorized actor accessed systems and acquired files containing employee and customer information. The bank notified federal law enforcement, implemented enhanced security controls, and provided credit monitoring services to affected individuals. 54 New Hampshire residents were notified.

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Incident timeline

undetected · 1 days

discovery → filing · 36 weeks / 253 days

Apr 11, 2023

Begins

Apr 12, 2023

Discovered

Nov 21, 2023

Scope determined

Dec 21, 2023

Filed

vs. sector median

+28 wks slower

This filing is one of 6 filings about the same incident.View merged incident

Linked disclosures

Why this link?

Regulatory filings (5) · sorted by filing gap

Vermont State AGbd_2dee8d0f47f231bc2023-12-21Verified
Montana State AGbd_4752d46a27914d1a2023-12-21Candidate
Massachusetts State AGbd_c1b3763023b7f8a72023-12-21Verified
California State AGbd_cc811a129570fcd52023-12-21Verified

Show 1 more filing ↓

SEC 8-Kbd_d3345e13b9cb6e072023-12-21Verified

Name: The Middlefield Banking Company
norm: the middlefield banking

Name: The Middlefield Banking Company
norm: the middlefield banking
Industry: Financial Servicesllm

Discovered: Apr 12, 2023
Breach occurred: Apr 11, 2023 – Apr 12, 2023
Undetected for: 1 dayoccurrence → discovery
Materiality determined: Nov 21, 2023
Notification sent: Dec 21, 2023
Affected individuals: 54state-resident count only
Data types: Identity (basic)Government ID
Attack vector: Unauthorized Access
MITRE ATT&CK: T1078 Valid Accounts
Threat actor: ExternalFinancial
Regulator citations: notified federal law enforcementproviding notice of this incident to relevant state and federal regulators
Initial access: valid_credentials

During the incident: Moved quickly to investigate and respond to the incident
Assess the security of Middlefield Bank systems
Identify potentially affected individuals
Notified federal law enforcement regarding the event
Working to implement additional safeguards and training to its employees
Providing access to credit monitoring services for individuals whose personal information was potentially affected by this incident, at no cost to these individuals
Providing impacted individuals with guidance on how to better protect against identity theft and fraud
Providing notice of this incident to relevant state and federal regulators, as necessary, and to the three major credit reporting agencies
Cooperating with its investigation
Changes made: Implemented enhanced security controls
Reviewed our existing policies and procedures relating to data protection and security
Source: Quoted from the filing itself, not independently verified.

Time to disclose: 36 weeks(253 days from discovery to filing)
Compliance flags: — (clock not assessable for this source)

Status: No extraction artifact recorded for this disclosure.

Filing propagation · 6 filings · 5 states

View merged incident ↗

Vermont State AGDec 21 · first

Montana State AGDec 21 · first

Massachusetts State AGDec 21 · first

California State AGDec 21 · first

SEC 8-KDec 21 · first

New Hampshire State AGDec 21 · first · this page

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://mm.nh.gov/files/uploads/doj/remote-docs/middlefield-banking-company-20231221.pdf
DisclosureLens links to the originating regulator URL — full filing bodies are not redistributed from public surfaces (§4.5).
Filed at: Dec 21, 2023
Raw hash: cee2ca005c717efbd2040eef9a2c1cdb11197553c70d972f1100dc2ac9c50d25

Linked disclosures

Regulatory filings (5) · sorted by filing gap

Reporting entityThe Middlefield Banking Company

Victim entityThe Middlefield Banking Company

Incidentdiscovered Apr 12, 2023

Stated responseMoved quickly to investigate and respond to the incident

Complianceclock not assessable

Extraction provenanceno artifact recorded

Source provenancemm.nh.gov