On April 26, 2022 8:06:50 AM UTC, Alessandro Vesely <[email protected]> wrote:
>On Mon 25/Apr/2022 05:56:46 +0200 Scott Kitterman wrote:
>>
>> How about something like this:
>>
>> 9.7 Determination of the Organizational Domain For Relaxed Alignment
>>
>> DMARC evaluation for relaxed alignment is highly sensitive to errors in the
>> determination of the organizational domain if the RFC5322.From domain does
>> not
>> have a published policy. If an incorrectly selected organizational domain is
>> a parent of the correct organizational domain, then relaxed alignment could
>> potentially allow a malicious sender to obtain DMARC PASS. This potential
>> exists for both the legacy [RFC 7489] and current [Section 4.8] methods for
>> determining the organizational domain.
>
>
>I object that this text undermines the robustness of the protocol and may
>sound like a campaign for strict alignment. Relaxed alignment is safer from a
>flexibility POV, as it accounts for occasional @hostname.example.com. It has
>played a relevant role in DMARC success, and it's not by chance the default.
>
>Here's an alternative text:
>
> DMARC evaluation for relaxed alignment is sensitive to errors in the
> determination of the organizational domain due to erroneous DNS settings by
> either the organizational domain or its PSD parent. If the PSD parent is
> incorrectly selected as organizational domain, then relaxed alignment can
> potentially allow a malicious sender to obtain DMARC PASS while
> impersonating the relevant organization. This potential exists for both
> the legacy [RFC 7489] and current [Section 4.8] methods for determining the
> organizational domain.
>
>
>> This issue is completely avoided by use of strict alignment and publishing
>> DMARC records for all domains/sub-domains used as RFC5322.From domain in an
>> organization's email.
>
>
> or by publishing psd=n.
>
>
>> For cases where strict alignment is not appropriate, this issue can be
>> mitigated by periodically checking the DMARC records, if any, of PSDs above
>> the organization's domains in the DNS tree and (for legacy [RFC 7489]
>> checking
>> that appropriate PSL entries remain present). If a PSD domain publishes a
>> DMARC record without the appropriate psd=y tag, organizational domain owners
>> can add psd=n to their organizational domain's DMARC record so that the PSD
>> record will not be incorrectly evaluated to be the organizational domain.
>
>
>The latter alternative is obviously easier than monitoring the DNS settings of
>the PSD parent, and has to be carried out anyway in case.
What specifically do you object to?
Do you think it's inaccurate that this concern is limited to relaxed alignment?
The specific suggestion you added (or by publishing psd=n) is already in the
text later on, so I'm not understanding what you think the problem is or what
you want to do about it?
Scott K
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