Greylock McKinnon Associates

Disclosed Feb 23, 2024352,965 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	NamesSocial Security numbers
Sector	Other · US
Status	Confirmed

Sources

Official noticeoag.ca.gov

California Attorney General breach notice: Greylock McKinnon Associates

Official noticejustice.oregon.gov

Oregon DOJ breach notice: Greylock McKinnon Associates

Newstechcrunch.com

Hackers stole 340,000 Social Security numbers from government consulting firm

Official noticein.gov

Indiana Attorney General 2024 data breach report: Greylock McKinnon Associates

Notices filed

Residents of INFeb 23, 2024

Indiana AG26,375 people

Residents of CAApr 5, 2024

California AGCount not stated

Residents of ORApr 5, 2024

Oregon DOJ341,650 people

TotalApr 5, 2024

Research341,650 people

Residents of CAJun 28, 2024

California AGCount not stated

Residents of INJun 28, 2024

Indiana AG17 people

History of this record

records2026-09-25

341650 to 352965by backfillSource

disclosed2026-09-25

2024-04-05 to 2024-02-23by backfillSource

attack2026-09-25

unknown to hackingby seedSource

data_types2026-09-25

[] to ["names","ssn"]by seedSource

records_basis2026-09-25

empty to organizationby seedSource

records2026-09-25

empty to 341650by seedSource

summary2026-09-25

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.by seedSource

title2026-09-25

empty to Government consulting firm says hackers stole up to 341,650 SSNsby seedSource

discovered2026-09-25

empty to 2024-02-07by backfillSource

disclosed2026-09-25

2024-06-28 to 2024-04-05by backfillSource

Added2026-09-25

First recordedby backfillSource

First seen 2026-09-25 (California AG), confirmed by California AG. Record counts are as reported. Not legal advice.

Everything about Greylock McKinnon Associates