FEDERALItem 8.01 · voluntaryHackingFinancial ServicesFinanceLowActive

The Middlefield Banking Company

bd_c3e9962da013c767 · schema v1 · pii pii-v1

Severity

Low

Discovered

Apr 12, 2023

Filed

Apr 21, 2023

To disclose

9 days

Affected

Not disclosed

Confidence

68%

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

Middlefield Banc Corp. learned of a cyber-attack on April 12, 2023, disrupting systems at its subsidiary, The Middlefield Banking Company. The Bank remediated the vulnerability, engaged forensic investigators, and notified law enforcement. The investigation is ongoing to determine if customer data was impacted. No material financial impact is currently expected.

J jump to incidentP pin to compareR raw source

Incident timeline

discovery → filing · 9 days

Apr 12, 2023

Discovered

Apr 21, 2023

Filed

vs. sector median

7 wks faster

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

Name: MIDDLEFIELD BANC CORP.
norm: middlefield banc
SEC CIK: 0000836147

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

Discovered: Apr 12, 2023
Materiality determined: —
Notification sent: —
Affected individuals: Not disclosed
Data types: —
Attack vector: Unknown
Threat actor: External

During the incident: The Bank took immediate action to remediate the security vulnerability
Retained a cybersecurity firm to investigate the nature and scope of the incident, evaluate systems and identify solutions, and confirm what data has been impacted by this event, if any
Notified law enforcement
Placed additional security measures in place
Continue to actively monitor any suspicious activity
Retained special legal counsel
Changes made: Took immediate action to remediate the security vulnerability
Placed additional security measures in place
Source: Quoted from the filing itself, not independently verified.

Time to disclose: 9 days(9 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 filing

Unlocks: discovery date, data types, affected count, compliance clock.

SEC 8-K / victim statementThis record

Unlocks: materiality, stated response, full audit trail. Ceiling removed.

Source URL: https://www.sec.gov/Archives/edgar/data/836147/000119312523110661/
DisclosureLens renders the full SEC/HHS filing inline below from the originating regulator’s public record (§4.5 fair report privilege).
Filed at: Apr 21, 2023
Raw hash: f45529a2539dab251b7504b6000690c58cdf9389ea384867c1821b6348dabe08

AI-assisted summary above. The structured extract on this page was generated from the document below. Inspect the source to verify or correct any field.

text/html23.8 KB

Download View at source

Reporting entityMIDDLEFIELD BANC CORP.

Victim entityThe Middlefield Banking Company

Incidentdiscovered Apr 12, 2023

Stated responseThe Bank took immediate action to remediate the security vulnerability

Complianceclock not assessable

Extraction provenanceno artifact recorded

Source provenancewww.sec.gov

Source filing