DisclosureLens
HackingHealthcareTechnologyHealthcareVulnerability ExploitSupply Chain (3P Vendor)Customer Data InvolvedIdentity (basic)Government IDHealth (basic)PHIMediumContained

Blue Cross and Blue Shield of Massachusetts, Inc.

bd_249d2927c5e04cd8 · schema v1 · pii pii-v1

Severity

Medium

Discovered

Dec 10, 2024

Filed

Jul 7, 2025

To disclose

30 weeks

Affected

Not disclosed

Confidence

66%
Full breach record for Blue Cross and Blue Shield of Massachusetts, Inc. →16 incidents on file

Cierant Corporation, a distributed marketing software vendor for Blue Cross and Blue Shield of Massachusetts, disclosed a data security event involving a vulnerability in the third-party file transfer tool Cleo VLTrader. An unauthorized actor exploited this vulnerability to gain limited access to Cierant systems, potentially acquiring files containing personal information of approximately 1,422 Rhode Island residents. The incident was discovered on December 10, 2024. Cierant ceased use of the tool, rotated passwords, and is offering credit monitoring.

California clockDiscovered Dec 10, 2024 → Notified Jul 3, 2025205d ✗ CA 60-day late30 weeks discovery → filing

Incident timeline

undetected · 1 days
discovery → filing · 30 weeks / 209 days

Dec 9, 2024

Begins

Dec 10, 2024

Discovered

Jul 7, 2025

Filed

vs. sector median

+18 wks slower

Part of Cleo supply-chain incident (2025) — a supply-chain cascade affecting multiple organizations.View cascade →
Tracked as a single-filing incident — the only disclosure on record for this event so far.ConfirmedView incident

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.