HackingProfessional ServicesProfessional ServicesTargetedCustomer Data InvolvedIdentity (basic)Government IDFinancial accountMediumActive

L.M. Henderson & Company, LLP

bd_985f39c6cd3cd123 · schema v1 · pii pii-v1

Severity

Medium

Discovered

May 31, 2021

Filed

Sep 9, 2021

To disclose

14 weeks

Affected

4state residents only

Linked

3 filings

Confidence

65%

Full breach record for L.M. Henderson & Company, LLP →2 incidents on file

L.M. Henderson & Company, LLP notified clients of a data security incident detected in May 2021 involving unauthorized access to personal information including names, SSNs, and financial account data. The firm engaged cybersecurity counsel and law enforcement, and offered credit monitoring services.

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Incident timeline

undetected · 30 days

discovery → filing · 14 weeks / 101 days

May 1, 2021

Begins

May 31, 2021

Discovered

Sep 9, 2021

Filed

vs. sector median

4 wks faster

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

Indiana State AGbd_4cb5227a0e0261002021-09-07 · +2dVerified
New Hampshire State AGbd_a55c8dc5a098a63e2021-09-13 · +4dVerified

Name: L.M. Henderson & Company, LLP
norm: lm henderson

Name: L.M. Henderson & Company, LLP
norm: lm henderson
Industry: Professional Servicesllm

Discovered: May 31, 2021
Breach occurred: May 1, 2021 – May 31, 2021
Undetected for: 30 daysoccurrence → discovery
Materiality determined: —
Notification sent: Sep 7, 2021
Affected individuals: 4state-resident count only
Data types: Identity (basic)Government IDFinancial account
Data elements: Social Security numberDate of birth
Attack vector: Unauthorized Access
MITRE ATT&CK: T1078 Valid AccountsT1119 Automated Collection
Threat actor: ExternalFinancial
Regulator citations: notified law enforcement

During the incident: Launched an investigation
Engaged a national cybersecurity firm to assist in assessing the scope of the incident
Took steps to mitigate the potential impact to our clients
Notified law enforcement
Working with cybersecurity counsel
Working diligently alongside our IT professionals to review our current system, policies, and procedures and make any necessary adjustments
Arranged for you to enroll in a complimentary, identity theft protection services through IDX
Changes made: Review our current system, policies, and procedures and make any necessary adjustments
Source: Quoted from the filing itself, not independently verified.

Time to disclose: 14 weeks(101 days from discovery to filing)
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 ↗

Indiana State AGSep 7 · first

Montana State AG+2d · this page

New Hampshire State AG+6d

Pattern: first filing Sep 7 (IN), last Sep 13 (NH) — a 6-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://dojmt.gov/wp-content/uploads/OCP/consumer-notification-letter-13.pdf
DisclosureLens links to the originating regulator URL — full filing bodies are not redistributed from public surfaces (§4.5).
Filed at: Sep 9, 2021
Raw hash: 38d330610d1035f91228f153f8d48d8dcdc54a13ecec362ab20ff34245ba9d1f

Linked disclosures

Regulatory filings (2) · sorted by filing gap

Reporting entityL.M. Henderson & Company, LLP

Victim entityL.M. Henderson & Company, LLP

Incidentdiscovered May 31, 2021

Stated responseLaunched an investigation

Complianceclock not assessable

Extraction provenanceno artifact recorded

Source provenancedojmt.gov