Blue Cross and Blue Shield of Massachusetts, Inc.

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.

Affected (this filing): 1,422