DisclosureLens
HackingEducationMedium

Chester County Library System, PA

bd_19412a253040ab1e · schema v1 · pii pii-v1

Severity

Medium

Discovered

Oct 17, 2025

Filed

Oct 28, 2025

To disclose

11 days

Affected · nationwide

1,2811 in this filing

Linked

3 records

Confidence

55%
Full breach record for Chester County Library System, PA →

Chester County Library System experienced a data breach due to an external system breach (hacking) affecting 1281 individuals, including 1 Maine resident.

Maine clockDiscovered Oct 17, 2025 → Filed with AG Oct 28, 202511d ✓ ME AG ≤30d11 days 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 · 34 days
discovery → filing · 11 days

Sep 13, 2025

Begins

Oct 17, 2025

Discovered

Oct 28, 2025

Filed

This filing is one of 3 records about the same incident.View merged incident

Linked disclosures

Why this link?

Ransomware claims (1)

Regulatory filings (1) · sorted by filing gap

Filing propagation · 2 filings · 2 states

View merged incident ↗
Maine State AGOct 28 · first · this page
Massachusetts State AG+10d

Pattern: first filing Oct 28 (ME), last Nov 7 (MA) — a 10-day rolling notification. Rolling spreads often mean counsel is filing as thresholds trip per state. Why this link?

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.