On Thu, Sep 19, 2013 at 06:42:05PM +0100, Sabahattin Gucukoglu wrote:
On 19 Sep 2013, at 17:33, keld(_at_)keldix(_dot_)com wrote:
On Thu, Sep 19, 2013 at 09:37:18AM +0200, Rolf E. Sonneveld wrote:
So first things first, let's start with a proper threat analysis.
I don't know how to write such an analysis, and it seems like red tape to
me.
I am just advocating that we migrate SMTP to TLS, and then I want a plan
that could evolve into an succesful migration, without hurting
interoperablity.
I've already explained in one way how interoperability is guaranteed to be
hurt, even if your threat model only includes passive attackers. And I'm
really not sure I'm happy about weakening TLS by making verification optional
without making it very clear to implementers that their choice to use a
CA-signed certificate is completely undermined for the sake of those who
don't, regardless of how pointless verification may be.
And I already outlined a way to accomodate your concerns.
You would strengthen SMTP security overall by employing TLS.
I understand that it is only a few SMTP implementations that have the problems
you described. And those implementations are most likely contaminated anyway.
CA-signen certifications are most likely also contaminated, and self-signed
certificates
are most likely having more chances of not being contaminated.
But look, what *is* your threat model? Who are you up against? What
capabilities do they have? Is this about Prism, or something much worse
involving active network attackers or server takeover? Without this we really
don't know how we can best solve the problem, and even if we did, we'd
probably disagree on the means, or the utility, or the interoperability
problems.
What are the requirements for the specs for a threat analysis?
Who made such a requirement?
Can you provide a link to the requirements?
And a good example of one?
best regards
Keld
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