Re: [dmarc-ietf] Response to a claim in draft-crocker-dmarc-author-00 security considerations

Dave Crocker <dcrocker@gmail.com> Mon, 20 July 2020 00:52 UTC

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To: "Murray S. Kucherawy" <superuser@gmail.com>
Cc: IETF DMARC WG <dmarc@ietf.org>
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From: Dave Crocker <dcrocker@gmail.com>
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Date: Sun, 19 Jul 2020 17:52:44 -0700
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Subject: Re: [dmarc-ietf] Response to a claim in draft-crocker-dmarc-author-00 security considerations
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On 7/19/2020 5:04 PM, Murray S. Kucherawy wrote:
> On Sun, Jul 19, 2020 at 11:33 AM Dave Crocker <dcrocker@gmail.com 
> <mailto:dcrocker@gmail.com>> wrote:
>
>     The track record is that people are unreliable at this.
>
>     There is quite a bit of distance between 'unreliable' and 'blindly
>     open and read absolutely everything'.
>
> Is there?

Yes.


> If there's no part of the From field that can be considered reliable, 
> then by opening even this email am I not exhibiting nearly-blind faith 
> that the indicators I can see (in this case the string "Dave Crocker 
> (gmail.com <http://gmail.com>)") have not been falsely generated?  How 
> is this message, in terms of its trustworthiness, different from any 
> other?

It's an act of curiosity, not faith.  You know that mail can be 
spoofed.  You might even suspect that I'm capable of lying. (Silly, I 
know, but...) Or that I might be wrong. (Truly a foolish thought.)  So 
the process of deciding on the validity and worth of my message is 
incremental and heuristic.

Human evaluation processes vary, but mostly are pretty complex. Except 
when they aren't, though then it's often problematic.

Mostly, your line of comments is trying to apply logical reasoning, 
which is rarely helpful in assessing human behavior.

All of which is why this is a really terrible forum for making 
assertions or, worse, decisions, about end-user behavior.

Whereas talking in terms of receiving filtering engines is both simpler 
and more useful.

d/

-- 
Dave Crocker
Brandenburg InternetWorking
bbiw.net