SMTP over TLS for this list (was: RE: WG Review: Open PluggableEdge Services (opes))

[Paul Hoffman / IMC]

At 3:24 PM -0600 6/18/01, Vernon Schryver wrote:
>If only to set a good example for the world, could somebody please
>arrange to have the IETF mailing lists, starting with this one, create
>and publish its own certificate()s and notice and use STARTTLS?

If that happened and it was trumpeted, people would then start to 
assume that SMTP over TLS assures that the messages that appear on 
the list are securely the ones that were sent by the sender. Nothing 
could be further from the truth. SMTP over TLS is a hop-by-hop 
protocol, and protecting one hop in a chain does not protect the 
chain. Further, it is the job of the SMTP server on each hop to 
change the message, at least in the headers, and possibly in the body.

SMTP over TLS has many good features: it lets the two SMTP servers 
authenticate each other, it prevents snooping, and it prevents active 
attackers from changing messages. It does not prevent SMTP servers on 
any hop from changing messages.

Giving folks a false sense of security is a bad example, not a good one.

--Paul Hoffman, Director
--Internet Mail Consortium