Blue Cross and Blue Shield of Massachusetts, Inc.
bd_154646e20b01c5db · schema v1 · pii pii-v1
Full breach record for Blue Cross and Blue Shield of Massachusetts, Inc. →16 incidents on fileCierant Corporation, on behalf of Blue Cross and Blue Shield of Massachusetts, disclosed a data security event involving the third-party file transfer tool Cleo VLTrader. Cierant detected suspicious activity on December 10, 2024, and determined an unauthorized actor exploited a vulnerability in the tool to access systems and potentially acquire files. Personal information, including identity data, may have been involved. Cierant ceased use of the tool, rotated passwords, enhanced security controls, and notified law enforcement and regulators. Affected individuals are offered 12 months of credit monitoring.
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Incident timeline
Dec 10, 2024
Discovered
Jul 7, 2025
Filed
vs. sector median
+21 wks slower
Linked disclosures
Why this link?Regulatory filings (1) · sorted by filing gap
- California State AGbd_249d2927c5e04cd82025-07-07Candidate
Filing propagation · 2 filings · 2 states
View merged incident ↗Evidence ladder
Attacker assertion only. Establishes: claim date, group, alleged victim.
Unlocks: incident narrative, operational impact. Still no compliance clock.
Unlocks: discovery date, data types, affected count, compliance clock.
Unlocks: materiality, stated response, full audit trail. Ceiling removed.