HackingProfessional ServicesProfessional ServicesStolen CredentialsData ExfiltratedCustomer Data InvolvedIdentity (basic)Government IDPHIHealth (basic)HighContained

Greylock McKinnon Associates

bd_4f59e4feb1207f51 · schema v1 · pii pii-v1

Severity

High

Discovered

May 30, 2023

Filed

Apr 5, 2024

To disclose

44 weeks

Affected · nationwide

15,2441,820 in this filing

Linked

12 filings

Confidence

66%

Full breach record for Greylock McKinnon Associates →4 incidents on file

Greylock McKinnon Associates, Inc. (GMA) notified South Carolina regulators of a cyberattack involving personal and Medicare information of individuals whose data GMA held from the DOJ. GMA detected unusual activity on May 30, 2023. Affected data included names, DOBs, addresses, Medicare numbers (containing SSNs), and medical info. GMA engaged forensic specialists, notified law enforcement/DOJ, deleted data, and offered 24-month credit monitoring. Specific state counts were listed for Texas (13,379), Rhode Island (154), and Puerto Rico (171).

J jump to incidentP pin to compareR raw source

South Carolina clock✓ SC CRA notice due44 weeks discovery → filing

⚠ unattributedNo provenance was recorded for this discovery date and it matches no other date on the record. It may be correct, but it is not independently grounded.

Incident timeline

discovery → filing · 44 weeks / 311 days

May 30, 2023

Discovered

Apr 5, 2024

Filed

vs. sector median

+25 wks slower

This filing is one of 12 filings about the same incident.View merged incident

Linked disclosures

Why this link?

Regulatory filings (10) · sorted by filing gap

Maine State AGbd_524d78fcdff1e19d2024-04-05Verified
Oregon State AGbd_ba7fccfadfcbb07d2024-04-05Verified
California State AGbd_c55a125d8e9e0f582024-04-05Verified
New Hampshire State AGbd_8b7ba321f28889a02024-04-04 · +1dVerified

Show 6 more filings ↓up to 42d gap

Washington State AGbd_862de986dcc37c522024-04-16 · +11dVerified
Montana State AGbd_08e358e2c4d44d732024-02-23 · +42dVerified
New Hampshire State AGbd_8b8abd614469d3d92024-02-23 · +42dVerified
Maine State AGbd_e0ca51cf3adad76c2024-02-23 · +42dVerified
Massachusetts State AGbd_e352425b0bc9b1d92024-02-23 · +42dCandidate
Indiana State AGbd_ebe27468fd5864a12024-02-23 · +42dVerified

Showing first 10 of 11 linked disclosures.

Name: Greylock McKinnon Associates
norm: greylock mckinnon associates

Name: Greylock McKinnon Associates
norm: greylock mckinnon associates
Industry: Professional Servicesllm

Discovered: May 30, 2023
Materiality determined: —
Notification sent: Apr 4, 2024
Affected individuals: 15,244state + nationwide
Data types: Identity (basic)Government IDPHIHealth (basic)
Data elements: Social Security numberDate of birthMedical information
Attack vector: Unauthorized Access
MITRE ATT&CK: T1078 Valid Accounts
Threat actor: External
Regulator citations: Notified law enforcement and the DOJCenters for Medicare and Medicaid Services will begin to monitor for any improper use of your Medicare information
Initial access: valid_credentials

During the incident: Consulted with third-party cybersecurity specialists to assist with our response to the incident
Notified law enforcement and the DOJ
Deleted DOJ data from its systems after the incident
Changes made: Offering complimentary access to Single Bureau Credit Monitoring/Single Bureau Credit Report/Single Bureau Credit Score services for 24 months
Providing proactive fraud assistance through Cyberscout through Identity Force
Source: Quoted from the filing itself, not independently verified.

Time to disclose: 44 weeks(311 days from discovery to filing)
Compliance flags: SC CRA notice due
Discovery-date grounding: unattributedNo provenance was recorded for this discovery date and it matches no other date on the record. It may be correct, but it is not independently grounded.

Status: No extraction artifact recorded for this disclosure.

Filing propagation · 11 filings · 9 states

View merged incident ↗

Montana State AGFeb 23 · first

New Hampshire State AGFeb 23 · first

Maine State AGFeb 23 · first

Massachusetts State AGFeb 23 · first

Indiana State AGFeb 23 · first

New Hampshire State AG+41d

Maine State AG+42d

Oregon State AG+42d

California State AG+42d

South Carolina State AG+42d · this page

Washington State AG+53d

Pattern: first filing Feb 23 (MT), last Apr 16 (WA) — a 53-day rolling notification. Rolling spreads often mean counsel is filing as thresholds trip per state. Why this link?

Cascade drawn from the first 10 linked disclosures of 11 — the full spread may be wider.

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://consumer.sc.gov/sites/consumer/files/Documents/Security%20Breach%20Notices/GreylockMcKinnon%26Associates.pdf
DisclosureLens links to the originating regulator URL — full filing bodies are not redistributed from public surfaces (§4.5).
Filed at: Apr 5, 2024
Raw hash: 5a8499c9d4f740cfdb4fb0fcb017b23db78deaaf68c629a7464a8061b57600e9

Linked disclosures

Regulatory filings (10) · sorted by filing gap

Reporting entityGreylock McKinnon Associates

Victim entityGreylock McKinnon Associates

Incidentdiscovered May 30, 2023

Stated responseConsulted with third-party cybersecurity specialists to assist with our response to the incident

ComplianceSC CRA notice due

Extraction provenanceno artifact recorded

Source provenanceconsumer.sc.gov