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

"Murray S. Kucherawy" <superuser@gmail.com> Mon, 20 July 2020 00:05 UTC

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From: "Murray S. Kucherawy" <superuser@gmail.com>
Date: Sun, 19 Jul 2020 17:04:46 -0700
Message-ID: <CAL0qLwb2Ufw1HZBoCDccj2KBqtOHnmcmPWiuqYtGGQZbUDkBEg@mail.gmail.com>
To: Dave Crocker <dcrocker@gmail.com>
Cc: IETF DMARC WG <dmarc@ietf.org>
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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 Sun, Jul 19, 2020 at 11:33 AM Dave Crocker <dcrocker@gmail.com> wrote:

> On 7/19/2020 11:08 AM, Murray S. Kucherawy wrote:
>
> gain: There is quite a bit of experience demonstrating that providing
>> trust indicators to end users does not produce reliable -- ie, useful --
>> decision-making by end users.
>>
> We appear to be talking past each other.  I wasn't talking about trust
> indicators, but rather whether the RFC5322.From domain is visible.  I don't
> have any reason yet to think trust indicators are effective.
>
> The view that the From: address, or domain, or Display-Name is used, by
> end-users, for assessing the trustworthiness of a message means it/they are
> used as trust indicators.
>
> 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?

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)")
have not been falsely generated?  How is this message, in terms of its
trustworthiness, different from any other?

-MSK

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