[radext] RADIUS/TLS with NULL cipher suites

[Alan DeKok <[e-mail]>]

  I ran across this recently.  The EU has "power systems and management" standards for RADIUS.  Think SCADA && associated systems which do command and control of industrial equipment.

  That's good, right?

 IEC 62351-3:2023 was released recently, and contains the following gems (summarized)

Table 9 - TLS 1.2 usable cipher suites
...
TLS_NULL_WITH_NULL_NULL	disallowed
TLS_RSA_WITH_NULL_MD5	disallowed
TLS_RSA_WITH_NULL_SHA256
...

  Uh... what?  NULL encryption is allowed?

  Couple that with the people using the default RADIIS/TLS secret of "radsec", and this proposal is *worse* than using RADIUS/UDP.  The User-Password fields will be obfuscated with a known shared secret, making them visible to anyone.

  So for 6614bis, we need to forbid the use of NULL cipher suites for TLS 1.2 and earlier.

  We can't fix this specification.  But we can issue our own counter-specification which goes "WHAT?  WHY WOULD YOU DO THAT?"

  RADIUS is a never-ending source of joy.

  Alan DeKok.