HackingProfessional ServicesProfessional ServicesData ExfiltratedTargetedIdentity (basic)MediumContained

Hallisey & D'Agostino, LLP

bd_f2f9d2090f5cd0f3 · schema v1 · pii pii-v1

Severity

Medium

Discovered

Oct 21, 2025

Filed

Apr 17, 2026

To disclose

25 weeks

Affected · nationwide

16,68374 in this filing

Linked

5 filings

Confidence

66%

Full breach record for Hallisey & D'Agostino, LLP →

Hallisey & D'Agostino, LLP, a tax and accounting firm in Connecticut, disclosed an external system breach (hacking) occurring between September 28 and October 22, 2025. The firm discovered unusual activity on October 21, 2025. Approximately 16,683 individuals were affected, including 74 Maine residents. Personal information, including names and other identifiers, was potentially acquired. The firm engaged external cybersecurity experts, notified the FBI, and offered 12 months of credit monitoring and identity protection services through IDX.

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Maine clockDiscovered Oct 21, 2025 → Filed with AG Apr 17, 2026178d ✗ ME AG >90d25 weeks discovery → filing

⚠ unattributedNo provenance was recorded for this discovery date and it matches no other date on the record. It may be correct, but it is not independently grounded.

Incident timeline

undetected · 23 days

discovery → filing · 25 weeks / 178 days

Sep 28, 2025

Begins

Oct 21, 2025

Discovered

Apr 17, 2026

Filed

vs. sector median

+7 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

Indiana State AGbd_647dbf9a138be25b2026-04-17Candidate
New Hampshire State AGbd_6d1636b0677487b42026-04-17Verified
Massachusetts State AGbd_65ace7cdc7cab0b12026-04-18 · +1dVerified
Vermont State AGbd_ee948235b7ce7dac2026-04-18 · +1dVerified

Name: Hallisey & D'Agostino, LLP
norm: hallisey d agostino
Domain: hdllpcpa.com

Name: Hallisey & D'Agostino, LLP
norm: hallisey d agostino
Domain: hdllpcpa.com
Industry: Professional Servicesllm

Discovered: Oct 21, 2025
Breach occurred: Sep 28, 2025 – Oct 22, 2025
Undetected for: 23 daysoccurrence → discovery
Materiality determined: —
Notification sent: Apr 17, 2026
Affected individuals: 16,683state + nationwide
Data types: Identity (basic)
Attack vector: Unauthorized Access
MITRE ATT&CK: T1190 Exploit Public-Facing ApplicationT1119 Automated Collection
Threat actor: ExternalFinancial
Regulator citations: Notified the Federal Bureau of Investigation
Initial access: exploit_public_facing

During the incident: Launched an investigation with the support of external cybersecurity experts
Took steps to secure our IT environment
Notified the Federal Bureau of Investigation
Offering you the opportunity to enroll in complimentary identity theft protection services through IDX
Changes made: Implementing enhanced security measures to help prevent a similar incident from occurring in the future
Source: Quoted from the filing itself, not independently verified.

Time to disclose: 25 weeks(178 days from discovery to filing)
Compliance flags: ME AG >90d · 178dME resident >60d · 178d
Discovery-date grounding: unattributedNo provenance was recorded for this discovery date and it matches no other date on the record. It may be correct, but it is not independently grounded.
Clock breakdown: Statute Window Elapsed Threshold Status
Maine
Discovered: Oct 21, 2025
→ Filed with AG: Apr 17, 2026
178d 90 days ME AG >90d
Maine
Discovered: Oct 21, 2025
→ Notified: Apr 17, 2026
178d 60 days (analyst band; statutory cap is 30 days) ME resident >60d

Statute	Window	Elapsed	Threshold	Status
Maine	Discovered: Oct 21, 2025 → Filed with AG: Apr 17, 2026	178d	90 days	ME AG >90d
Maine	Discovered: Oct 21, 2025 → Notified: Apr 17, 2026	178d	60 days (analyst band; statutory cap is 30 days)	ME resident >60d

Status: No extraction artifact recorded for this disclosure.

Filing propagation · 5 filings · 5 states

View merged incident ↗

Indiana State AGApr 17 · first

New Hampshire State AGApr 17 · first

Maine State AGApr 17 · first · this page

Massachusetts State AG+1d

Vermont 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://www.maine.gov/agviewer/content/ag/985235c7-cb95-4be2-8792-a1252b4f8318/385fc975-ad5f-4530-82f8-93777baa83ed.html
DisclosureLens links to the originating regulator URL — full filing bodies are not redistributed from public surfaces (§4.5).
Filed at: Apr 17, 2026
Raw hash: 42dda78a6572b79020e5f26906c4b3c7a7ffc16726cc798a9159458e7dfb0fe0

Linked disclosures

Regulatory filings (4) · sorted by filing gap

Reporting entityHallisey & D'Agostino, LLP

Victim entityHallisey & D'Agostino, LLP

Incidentdiscovered Oct 21, 2025

Stated responseLaunched an investigation with the support of external cybersecurity experts

ComplianceME AG >90d

Extraction provenanceno artifact recorded

Source provenancewww.maine.gov