HackingProfessional ServicesProfessional ServicesStolen CredentialsCapture Stored DataData ExfiltratedTargetedIdentity (basic)Government IDFinancial accountMediumContained

Barton Gilman LLP

bd_598fd2d5e12c9d54 · schema v1 · pii pii-v1

Severity

Medium

Discovered

Sep 1, 2024

Filed

Dec 23, 2025

To disclose

16 months

Affected

52state residents only

Linked

5 filings

Confidence

66%

Full breach record for Barton Gilman LLP →

Barton Gilman LLP notified the NH Attorney General of unauthorized access to its network between Sept 13-26, 2024. Personal info of 52 NH residents (names, DOB, SSN, driver's license, financial accounts) was removed. Discovery occurred in Sept 2024. Notification sent Dec 23, 2025. Response included federal law enforcement notification and 12 months of credit monitoring via TransUnion.

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Incident timeline

Sep 13, 2024

Begins

Dec 23, 2025

Filed

vs. sector median

+51 wks slower

This filing is one of 5 about the same incident.View merged incident

Linked disclosures

Why this link?

Regulatory filings (4) · sorted by filing gap

Vermont State AGbd_0923a90f1999f7462025-12-23Candidate
Maine State AGbd_14ec9c5b447c32422025-12-23Verified
Indiana State AGbd_6f242b5c4968fe202025-12-23Verified
Massachusetts State AGbd_43fc4dd61c86c5762025-12-24 · +1dVerified

Name: Mullen Coughlin LLC
norm: mullen coughlin

Name: Barton Gilman LLP
norm: barton gilman
Industry: Professional Servicesllm

Discovered: Sep 1, 2024
Breach occurred: Sep 13, 2024 – Sep 26, 2024
Materiality determined: —
Notification sent: Dec 23, 2025
Affected individuals: 52state-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 AccountsT1041 Exfiltration Over C2 Channel
Threat actor: ExternalFinancial
Regulator citations: Notified federal law enforcementProviding written notice to relevant state regulators
Initial access: valid_credentials

During the incident: Began working with third party resources to investigate the nature and scope of the event
Notified federal law enforcement regarding the event
Providing access to credit monitoring services for twelve (12) months, through TransUnion
Providing impacted individuals with guidance on how to better protect against identity theft and fraud
Providing written notice of this incident to relevant state regulators
Providing written notice to the three major credit reporting agencies, Equifax, Experian, and TransUnion
Changes made: Implementing additional security measures to further protect against similar incidents occurring in the future
Source: Quoted from the filing itself, not independently verified.

Time to disclose: 16 months(478 days from discovery to filing)
Compliance flags: — (clock not assessable for this source)

Status: No extraction artifact recorded for this disclosure.

Filing propagation · 5 filings · 5 states

View merged incident ↗

Vermont State AGDec 23 · first

Maine State AGDec 23 · first

Indiana State AGDec 23 · first

New Hampshire State AGDec 23 · first · this page

Massachusetts State AG+1d

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/barton-gilman-20251223.pdf
DisclosureLens links to the originating regulator URL — full filing bodies are not redistributed from public surfaces (§4.5).
Filed at: Dec 23, 2025
Raw hash: fce4d56f675980c0f187209623f7e114c934ab5b12eec3434711caf7b98c31b4

Linked disclosures

Regulatory filings (4) · sorted by filing gap

Reporting entityMullen Coughlin LLC

Victim entityBarton Gilman LLP

Incidentdiscovered Sep 1, 2024

Stated responseBegan working with third party resources to investigate the nature and scope of the event

Complianceclock not assessable

Extraction provenanceno artifact recorded

Source provenancemm.nh.gov