A real example, with names RE: "Adult supervision"

[Keith Moore]

the problem with two ports is that (besides wasting scarce ports),
in the case of clients that will downgrade from TLS to non-TLS
if TLS doesn't work, it's fairly easy for an active attacker 
to force the downgrade, and thus, to force the conversation to
appear in cleartext.  what I was presuming is that sending a TCP
RST was easier for an attacker than say, hijacking the TLS connection 
to negotiate a weak cipher.  I thought this had been written up 
somewhere, but I can't remember where.  maybe on iana.org?

but I think this is a good example of something that *should* be
written up, at least on a web page.

Keith

On Thu, 8 May 2003 15:26:50 +0300
<john.loughney at nokia.com> wrote:

> Hi Keith,
> 
> > do you think writing up 30 pages of detailed explanation is 
> > constructive?
> 
> In some cases a 2 or 5 page document would be enough, at least for
> me.  Many times, I am just looking for documentation why I should
> or should not do 'x'.  Here is a good example, actually involving
> you.
> 
> When I took over the editorship of the Diameter Base spec, I
> was given a comment by the IESG that using different ports
> for TLS & non-TLS traffic violated a long-held IESG policy.  Of course,
> this policy is not written down.  As I have certain job responsibilities,
> folks at home were asking me what problems are caused by this,
> for which I had no answer.  After some pestering, someone, Bert W.
> I think, pointed me to an SMTP RFC with some discussion about port
> usage ... it didn't really provide me with convincing material,
> but I was motivated to get the doc done, so I made the fix.
> 
> A bit later, in another WG, the same issue came up again.  The WG 
> Security advisor, when asked about this mentioned - 'Oh, that was
> Keith's big thing ... mumble, mumble.'  Further mail exchanges with
> him & the responsible AD did not produce any insight or conclusions,
> so I'm left with little insight or understanding if it is allowed
> to use multiple ports or not.  Currently, the WG is leaning towards
> a 2-port model; does this mean we'll suffer a gotcha during IESG
> review?
> 
> John