Deprecating Insecure Practices in RADIUS

RADIUS crypto-agility was first mandated as future work by RFC 6421. The outcome of that work was the publication of RADIUS over TLS (RFC 6614) and RADIUS over DTLS (RFC 7360) as experimental documents. Those transport protocols have been in wide-spread use for many years in a wide range of networks, and have recently been standardized in [I-D.ietf-radext-radiusdtls-bis]. TLS has proven to be a useful replacment for UDP (RFC 2865) and TCP (RFC 6613) transports. With that knowledge, the continued use of insecure transports for RADIUS has serious and negative implications for privacy and security. The publication of the "BlastRADIUS" exploit has also shown that RADIUS security needs to be updated. It is no longer acceptable for RADIUS to rely on MD5 for security. It is no longer acceptable to send device or location information in clear text across the wider Internet. This document therefore deprecates many insecure practices in RADIUS, and mandates support for secure TLS-based transport layers. Related security issues with RADIUS are discussed, and recommendations are made for practices which increase both security and privacy.