HackingHealthcareHealthcareData ExfiltratedCustomer Data InvolvedDelayed DiscoveryPIIPHIIdentity (basic)Health (basic)LowContained

Tieu Dental Corporation

bd_ef1e883718516c4e · schema v1 · pii pii-v1

Severity

Low

Discovered

Jan 11, 2026

Filed

Mar 5, 2026

To disclose

8 weeks

Affected

Not disclosed

Linked

3 filings

Confidence

66%

Full breach record for Tieu Dental Corporation →

Tieu Dental Corporation notified Massachusetts residents of unauthorized access to its network between July 28-29, 2025. The company determined on January 11, 2026, that personal and health information, including full names, may have been accessed or acquired. The incident has been contained, and the company is offering one year of complimentary identity monitoring through Experian.

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Massachusetts clock⏱ MA AG >30d8 weeks discovery → filing

Incident timeline

undetected · 167 days

discovery → filing · 8 weeks / 53 days

Jul 28, 2025

Begins

Jan 11, 2026

Discovered

Mar 5, 2026

Filed

vs. sector median

3 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

California State AGbd_59f20023789244912026-03-05Candidate
HHS OCRbd_62287b3e2fb7b0fe2026-03-05Verified

Name: Tieu Dental Corporation
norm: tieu dental

Name: Tieu Dental Corporation
norm: tieu dental
Industry: Healthcarellm

Discovered: Jan 11, 2026
Breach occurred: Jul 28, 2025 – Jul 29, 2025
Undetected for: 167 daysoccurrence → discovery
Materiality determined: —
Notification sent: —
Affected individuals: Not disclosed
Data types: PIIPHIIdentity (basic)Health (basic)
Attack vector: Unauthorized Access
MITRE ATT&CK: T1078 Valid AccountsT1041 Exfiltration Over C2 Channel
Threat actor: External

During the incident: Launched an investigation
Contained and secured the network
Eradicated the threat
Working closely with third-party cybersecurity professionals
Conducted an extensive and comprehensive review of the impacted files
Offering a complimentary one-year membership of Experian IdentityWorks
Established a dedicated and confidential toll-free response line
Changes made: Reviewed and revised our information security practices
Implemented additional security measures to mitigate the chance of a similar event in the future
Source: Quoted from the filing itself, not independently verified.

Time to disclose: 8 weeks(53 days from discovery to filing)
Compliance flags: MA AG >30d
Discovery-date grounding: letter-groundedThe discovery date is the detection date narrated in the notification letter — the defensible tier.

Status: No extraction artifact recorded for this disclosure.

Filing propagation · 3 filings · 2 states

View merged incident ↗

California State AGMar 5 · first

HHS OCRMar 5 · first

Massachusetts State AGMar 5 · first · 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://www.mass.gov/doc/2026-331-tieu-dental-corporation/download
DisclosureLens links to the originating regulator URL — full filing bodies are not redistributed from public surfaces (§4.5).
Filed at: Mar 5, 2026
Raw hash: 532c860aa79fd9f42aae579372ff8881c7740387c8d06f5237385210270def58

Linked disclosures

Regulatory filings (2) · sorted by filing gap

Reporting entityTieu Dental Corporation

Victim entityTieu Dental Corporation

Incidentdiscovered Jan 11, 2026

Stated responseLaunched an investigation

ComplianceMA AG >30d

Extraction provenanceno artifact recorded

Source provenancewww.mass.gov