HackingGovernmentGovernmentStolen CredentialsData ExfiltratedCustomer Data InvolvedEmployee Data InvolvedIdentity (basic)Government IDFinancial accountPHIHealth (basic)MediumContained

The Town of Chester

bd_69809c87beb5fa42 · schema v1 · pii pii-v1

Severity

Medium

Discovered

Apr 28, 2025

Filed

Sep 5, 2025

To disclose

19 weeks

Affected

5state residents only

Linked

5 filings

Confidence

66%

Full breach record for The Town of Chester →

The Town of Chester, Massachusetts, notified the New Hampshire Attorney General of a data event involving unauthorized access to its email environment. The incident occurred between April 9 and April 29, 2025, and was discovered on April 28, 2025. The breach compromised names, Social Security numbers, driver's license numbers, financial account numbers, and personal health information. Five New Hampshire residents were affected. The Town engaged forensic specialists, retained legal counsel, and offered 24 months of credit monitoring.

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Incident timeline

undetected · 19 days

discovery → filing · 19 weeks / 130 days

Apr 9, 2025

Begins

Apr 28, 2025

Discovered

Sep 5, 2025

Filed

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

Massachusetts State AGbd_0a10671fcc18b6f42025-09-05Verified
Maine State AGbd_3855e06eac1d88be2025-09-05Candidate
Vermont State AGbd_5d80778b97c5b51e2025-09-05Verified
Illinois State AGbd_1141dd060e2bd59b2025-09-01 · +4dVerified

Name: The Town of Chester
norm: the town of chester

Name: The Town of Chester
norm: the town of chester
Industry: Governmentllm

Discovered: Apr 28, 2025
Breach occurred: Apr 9, 2025 – Apr 29, 2025
Undetected for: 19 daysoccurrence → discovery
Materiality determined: —
Notification sent: Sep 5, 2025
Affected individuals: 5state-resident count only
Data types: Identity (basic)Government IDFinancial accountPHIHealth (basic)
Attack vector: Unauthorized Access
MITRE ATT&CK: T1114 Email CollectionT1078 Valid Accounts
Threat actor: External
Regulator citations: Notified New Hampshire Attorney General's Consumer Protection Bureau
Initial access: valid_credentials

During the incident: Engaged a specialized cybersecurity firm to conduct a forensic investigation
Retained legal counsel
Notified its law firm
Began identifying the affected individuals in preparation for notice
Offered 24 months of complimentary credit monitoring services through Cyberscout/TransUnion
Changes made: Provided guidance on how to better protect against identity theft and fraud
Provided information on how to place a fraud alert and security freeze on one’s credit file
Provided contact details for the national consumer reporting agencies
Provided information on how to obtain a free credit report
Source: Quoted from the filing itself, not independently verified.

Time to disclose: 19 weeks(130 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 ↗

Illinois State AGSep 1 · first

Massachusetts State AG+4d

Maine State AG+4d

Vermont State AG+4d

New Hampshire State AG+4d · 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/town-chester-massachusetts-20250905.pdf
DisclosureLens links to the originating regulator URL — full filing bodies are not redistributed from public surfaces (§4.5).
Filed at: Sep 5, 2025
Raw hash: 9b97c8b51a8b7f39cfb9c804c18f3ca476261bac0fb5c2e4f6013deca1068f85

Linked disclosures

Regulatory filings (4) · sorted by filing gap

Reporting entityThe Town of Chester

Victim entityThe Town of Chester

Incidentdiscovered Apr 28, 2025

Stated responseEngaged a specialized cybersecurity firm to conduct a forensic investigation

Complianceclock not assessable

Extraction provenanceno artifact recorded

Source provenancemm.nh.gov