Cornerstone Healthcare Group Management Services
Disclosed Mar 14, 20242 years ago484,957 affectedConfirmed
Cornerstone Healthcare Group Management Services, the business associate (BA), reported that it experienced a hacking incident that compromised the protected health information (PHI) of 484,957 individuals. The PHI involved included names, addresses, dates of birth, Social Security numbers, drivers’ license numbers, financial information, health insurance information and clinical information. The notified HHS, the affected individuals, and the media. In response to the breach, the BA strengthened its technical safeguards. OCR provided technical assistance to the BA pertaining to the HIPAA Breach Notification and Security Rules.
What is known
| People affected | 484,957 (as reported to HHS) |
|---|---|
| Disclosed | Mar 14, 2024 |
| Happened | Dec 19, 2023 |
| Attack | Hacking |
| Data exposed | Names, Health |
| Sector | Healthcare · US |
| Status | Confirmed |
Sources
| Source | |
|---|---|
| California Attorney General breach notice: Cornerstone Healthcare Group Management Servicesoag.ca.gov · Official notice | Official notice |
| Vermont Attorney General: 2024-11-01 Cornerstone Healthcare Group Management Services Data Breach Notice to Consumersago.vermont.gov · Official notice | Official notice |
| Vermont Attorney General: 2024-07-01 Cornerstone Healthcare Group Management Services data Breach Notice to Consumersago.vermont.gov · Official notice | Official notice |
| HHS OCR breach report (archive, resolved): Cornerstone Healthcare Group Management Services (Business Associate, KY)ocrportal.hhs.gov · Official notice | Official notice |
Notices filed
| Where | Filed | People |
|---|---|---|
| HHS archivetotal | Mar 14, 2024 | 484,957 |
| Vermont AGresidents of VT | Jul 1, 2024 | |
| Vermont AGresidents of VT | Nov 1, 2024 | |
| California AGresidents of CA | Nov 2, 2024 |
History of this record
- 2026-09-25 · attack: unknown to hacking · backfill source
- 2026-09-25 · data_types: [] to ["names","health"] · backfill source
- 2026-09-25 · records_basis: empty to hhs · backfill source
- 2026-09-25 · records: empty to 484957 · backfill source
- 2026-09-25 · disclosed: 2024-07-01 to 2024-03-14 · backfill source
- 2026-09-25 · summary: empty to Cornerstone Healthcare Group Management Services, the business associate (BA), reported that it experienced a hacking incident that compromised the protected health information (PHI) of 484,957 individuals. The PHI involved included names, · backfill source
- 2026-09-25 · source: empty to https://ago.vermont.gov/document/2024-07-01-cornerstone-healthcare-group-management-services-data-breach-notice-consumers · backfill source
- 2026-09-25 · disclosed: 2024-11-01 to 2024-07-01 · backfill source
- 2026-09-25 · disclosed: 2024-11-02 to 2024-11-01 · backfill source
- 2026-09-25 · added · backfill source
First seen 2026-09-25 (California AG), confirmed by California AG. Record counts are as reported. Not legal advice.
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