HackingEducationEducationVulnerability ExploitTargetedData ExfiltratedIdentity (basic)Government IDHighContained

Riverdale Country School, Inc.

bd_2ec0f59d35cdb6f6 · schema v1 · pii pii-v1

Severity

High

Discovered

Apr 25, 2025

Filed

Jun 30, 2025

To disclose

9 weeks

Affected · nationwide

1,5241 in this filing

Linked

4 filings

Confidence

66%

Full breach record for Riverdale Country School, Inc. →

Riverdale Country School, Inc. reported a sophisticated cyber-attack occurring on February 5-6, 2025, which resulted in unauthorized access to names and Social Security numbers of 1,524 individuals. The breach was discovered on April 25, 2025. The school notified federal law enforcement and provided 12 months of credit monitoring via Experian to affected individuals.

J jump to incidentP pin to compareR raw source

Maine clockDiscovered Apr 25, 2025 → Filed with AG Jun 30, 202566d ⏱ ME AG >30d9 weeks discovery → filing

⚠ AG web formThe discovery date came from the AG web-form field, which is systematically later than the detection date stated in the letter. Treat the clock as indicative.

Incident timeline

undetected · 79 days

discovery → filing · 9 weeks / 66 days

Feb 5, 2025

Begins

Apr 25, 2025

Discovered

Jun 30, 2025

Filed

vs. sector median

+1 wks slower

This filing is one of 4 about the same incident.View merged incident

Linked disclosures

Why this link?

Ransomware claims (2)

Leak Siteransomhubbd_83b025fabf204e1e2025-02-07 · +143dVerified by operator
Leak Siteransomhubbd_ca330bcf1d25afe12025-02-05 · +145dVerified by operator

Regulatory filings (1) · sorted by filing gap

Massachusetts State AGbd_0d30d2b140332eea2025-06-30Verified

Name: Riverdale Country School, Inc.
norm: riverdale country school
Domain: riverdale.edu
Industry: Education

Name: Riverdale Country School, Inc.
norm: riverdale country school
Domain: riverdale.edu
Industry: Education
Industry: Educationllm

Discovered: Apr 25, 2025
Breach occurred: Feb 5, 2025 – Feb 6, 2025
Undetected for: 79 daysoccurrence → discovery
Materiality determined: —
Notification sent: Jun 30, 2025
Affected individuals: 1,524state + nationwide
Data types: Identity (basic)Government ID
Attack vector: Unauthorized Access
MITRE ATT&CK: T1190 Exploit Public-Facing ApplicationT1078 Valid Accounts
Threat actor: ExternalFinancial
Regulator citations: Notified relevant state regulators, as necessary
Initial access: exploit_public_facing

During the incident: Moved quickly to investigate and respond to the incident
Assessed the security of Riverdale systems
Identified potentially affected individuals
Notified federal law enforcement regarding the event
Provided access to credit monitoring services for twelve (12) months, through Experian
Provided impacted individuals with guidance on how to better protect against identity theft and fraud
Changes made: Implementing additional safeguards and training to its employees
Source: Quoted from the filing itself, not independently verified.

Time to disclose: 9 weeks(66 days from discovery to filing)
Compliance flags: ME AG >30d · 66dLeak >90d
Discovery-date grounding: AG web formThe discovery date came from the AG web-form field, which is systematically later than the detection date stated in the letter. Treat the clock as indicative.
Clock breakdown: Statute Window Elapsed Threshold Status
Maine
Discovered: Apr 25, 2025
→ Filed with AG: Jun 30, 2025
66d 30 days (soft) ME AG >30d

Statute	Window	Elapsed	Threshold	Status
Maine	Discovered: Apr 25, 2025 → Filed with AG: Jun 30, 2025	66d	30 days (soft)	ME AG >30d

Status: No extraction artifact recorded for this disclosure.

Filing propagation · 2 filings · 2 states

View merged incident ↗

Massachusetts State AGJun 30 · first

Maine State AGJun 30 · 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.maine.gov/agviewer/content/ag/985235c7-cb95-4be2-8792-a1252b4f8318/d254fe62-1a28-4e77-8a3f-d49e76d3e54d.html
DisclosureLens links to the originating regulator URL — full filing bodies are not redistributed from public surfaces (§4.5).
Filed at: Jun 30, 2025
Raw hash: 1813c3e6f72227d9fc60143bb52c48749fa2bfc3f791331971d546f3ffa0c1dd

Linked disclosures

Ransomware claims (2)

Regulatory filings (1) · sorted by filing gap

Reporting entityRiverdale Country School, Inc.

Victim entityRiverdale Country School, Inc.

Incidentdiscovered Apr 25, 2025

Stated responseMoved quickly to investigate and respond to the incident

ComplianceME AG >30d

Extraction provenanceno artifact recorded

Source provenancewww.maine.gov