Greylock McKinnon Associates
Disclosed Feb 23, 20242 years ago352,965 affectedConfirmed
Government consulting firm says hackers stole up to 341,650 SSNs
Economic and litigation consulting firm Greylock McKinnon Associates disclosed that a May 2023 cyberattack exposed data including as many as 341,650 Social Security numbers, posting its notice on Maine's breach website.
What is known
| People affected | 352,965 (as reported by the organization) |
|---|---|
| Disclosed | Feb 23, 2024 |
| Discovered | Feb 7, 2024 |
| Happened | May 30, 2023 |
| Attack | Hacking |
| Data exposed | Names, Social Security numbers |
| Sector | Other · US |
| Status | Confirmed |
Sources
| Source | |
|---|---|
| California Attorney General breach notice: Greylock McKinnon Associatesoag.ca.gov · Official notice | Official notice |
| Oregon DOJ breach notice: Greylock McKinnon Associatesjustice.oregon.gov · Official notice | Official notice |
| Hackers stole 340,000 Social Security numbers from government consulting firmtechcrunch.com · News | News |
| Indiana Attorney General 2024 data breach report: Greylock McKinnon Associatesin.gov · Official notice | Official notice |
Notices filed
| Where | Filed | People |
|---|---|---|
| Indiana AGresidents of IN | Feb 23, 2024 | 26,375 |
| California AGresidents of CA | Apr 5, 2024 | |
| Oregon DOJresidents of OR | Apr 5, 2024 | 341,650 |
| Researchtotal | Apr 5, 2024 | 341,650 |
| California AGresidents of CA | Jun 28, 2024 | |
| Indiana AGresidents of IN | Jun 28, 2024 | 17 |
History of this record
- 2026-09-25 · records: 341650 to 352965 · backfill source
- 2026-09-25 · disclosed: 2024-04-05 to 2024-02-23 · backfill source
- 2026-09-25 · attack: unknown to hacking · seed source
- 2026-09-25 · data_types: [] to ["names","ssn"] · seed source
- 2026-09-25 · records_basis: empty to organization · seed source
- 2026-09-25 · records: empty to 341650 · seed source
- 2026-09-25 · summary: empty to Economic and litigation consulting firm Greylock McKinnon Associates disclosed that a May 2023 cyberattack exposed data including as many as 341,650 Social Security numbers, posting its notice on Maine's breach website. · seed source
- 2026-09-25 · title: empty to Government consulting firm says hackers stole up to 341,650 SSNs · seed source
- 2026-09-25 · discovered: empty to 2024-02-07 · backfill source
- 2026-09-25 · disclosed: 2024-06-28 to 2024-04-05 · 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.