HackingFinancial ServicesFinanceStolen CredentialsCustomer Data InvolvedEmployee Data InvolvedPIIFinancial accountLowContained

The Middlefield Banking Company

bd_4752d46a27914d1a · schema v1 · pii pii-v1

Severity

Low

Discovered

Apr 12, 2023

Filed

Dec 21, 2023

To disclose

36 weeks

Affected

33state residents only

Linked

6 filings

Confidence

65%

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

Middlefield Banking Company notified affected individuals of a security incident occurring April 11-12, 2023. An unauthorized actor accessed systems, acquiring files containing names and account numbers of employees and customers. The bank engaged outside specialists, notified federal law enforcement, and provided 12 months of credit monitoring. Notification was sent December 21, 2023.

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Incident timeline

undetected · 1 days

discovery → filing · 36 weeks / 253 days

Apr 11, 2023

Begins

Apr 12, 2023

Discovered

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
New Hampshire State AGbd_719ea19c8e0056802023-12-21Verified
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: —
Notification sent: Dec 21, 2023
Affected individuals: 33state-resident count only
Data types: PIIFinancial account
Attack vector: Unauthorized Access
MITRE ATT&CK: T1078 Valid AccountsT1119 Automated Collection
Threat actor: ExternalFinancial
Regulator citations: prompt and continued correspondence with federal law enforcement authorities
Initial access: valid_credentials

During the incident: Launched an investigation with the assistance of outside specialists
Conducted a thorough review of the data
Prompt and continued correspondence with federal law enforcement authorities
Provided 12 months of complimentary access to credit monitoring and identity restoration services
Changes made: Reviewed existing policies and procedures relating to data protection and security
Implemented enhanced security controls
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

New Hampshire State AGDec 21 · first

Massachusetts State AGDec 21 · first

California State AGDec 21 · first

SEC 8-KDec 21 · first

Montana 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://dojmt.gov/wp-content/uploads/OCP/Consumer-notification-letter-971.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: 5cb807290cb03c4ab8e26a98db90e46f7ada4185b58b99d101f4d834b18f3c05

Linked disclosures

Regulatory filings (5) · sorted by filing gap

Reporting entityThe Middlefield Banking Company

Victim entityThe Middlefield Banking Company

Incidentdiscovered Apr 12, 2023

Stated responseLaunched an investigation with the assistance of outside specialists

Complianceclock not assessable

Extraction provenanceno artifact recorded

Source provenancedojmt.gov