ETSI has released TS 103 523-2, a new specification for the Transport Layer Middlebox Security Protocol (TLMSP) designed to enable fine-grained access control for network middleboxes in 5G and modern infrastructures. This protocol allows endpoints to classify traffic into specific contexts and assign distinct read, delete, or write permissions to authorized middleboxes, adhering to the principle of least privilege without requiring intrusive break-and-inspect methods. By integrating features like on-path middlebox discovery, auditing, and adaptive message formats, TLMSP supports secure cyber defense and operational visibility while protecting user data from unauthorized access. A reference implementation is available for developers to facilitate the deployment of these enhanced security mechanisms in regulated industries and content delivery networks.
Keywords: middlebox security, fine-grained permissions, encrypted traffic, least privilege, endpoint control