HackingProfessional ServicesProfessional ServicesStolen CredentialsData ExfiltratedTargetedPIIIdentity (basic)Government IDMediumContained

Michael J. Gavin CPA PLLC

bd_daa07fd7713cc770 · schema v1 · pii pii-v1

Severity

Medium

Discovered

Mar 8, 2023

Filed

May 11, 2023

To disclose

9 weeks

Affected

1state residents only

Confidence

65%

Full breach record for Michael J. Gavin CPA PLLC →

Michael J. Gavin CPA, PLLC notified Montana residents of a security incident where unauthorized actors accessed an office computer between Nov 2022 and Mar 2023, fraudulently filing tax returns. The firm engaged cybersecurity specialists, secured its network, and reported the incident to the IRS. Affected individuals were offered 12 months of credit monitoring.

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Incident timeline

undetected · 118 days

discovery → filing · 9 weeks / 64 days

Nov 10, 2022

Begins

Mar 8, 2023

Discovered

May 11, 2023

Filed

vs. sector median

10 wks faster

Tracked as a single-filing incident — the only disclosure on record for this event so far.Confirmed1 affectedView incident

Name: Michael J. Gavin CPA PLLC
norm: michael j gavin cpa

Name: Michael J. Gavin CPA PLLC
norm: michael j gavin cpa
Industry: Professional Servicesllm

Discovered: Mar 8, 2023
Breach occurred: Nov 10, 2022 – Mar 11, 2023
Undetected for: 118 daysoccurrence → discovery
Materiality determined: —
Notification sent: May 11, 2023
Affected individuals: 1state-resident count only
Data types: PIIIdentity (basic)Government ID
Attack vector: Unauthorized Access
MITRE ATT&CK: T1078 Valid AccountsT1041 Exfiltration Over C2 Channel
Threat actor: ExternalFinancial
Regulator citations: Reported this event to the IRS
Initial access: valid_credentials

During the incident: Took steps to secure our network
Launched an investigation with the assistance of industry-leading cyber security specialists
Reviewed existing policies and procedures
Implemented additional safeguards
Reported this event to the IRS
Offering 12 months of complimentary credit monitoring through IDX
Changes made: Reviewing existing policies and procedures
Implementing additional safeguards to further protect against similar events
Source: Quoted from the filing itself, not independently verified.

Time to disclose: 9 weeks(64 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 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-264.pdf
DisclosureLens links to the originating regulator URL — full filing bodies are not redistributed from public surfaces (§4.5).
Filed at: May 11, 2023
Raw hash: 635a36fa699a4e67ad014df21e02c9706ec062a97f89be6c530fe5be1a448e71

Reporting entityMichael J. Gavin CPA PLLC

Victim entityMichael J. Gavin CPA PLLC

Incidentdiscovered Mar 8, 2023

Stated responseTook steps to secure our network

Complianceclock not assessable

Extraction provenanceno artifact recorded

Source provenancedojmt.gov