Re: [dmarc-ietf] Authentication of reports

Michael Thomas <mike@mtcc.com> Wed, 20 January 2021 23:02 UTC

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From: Michael Thomas <mike@mtcc.com>
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Date: Wed, 20 Jan 2021 15:01:55 -0800
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Subject: Re: [dmarc-ietf] Authentication of reports
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On 1/20/21 2:59 PM, Seth Blank wrote:
> Michael, please open a ticket. I think you're right and some 
> consideration around this is needed in the document.

What about the https part? If it's not in scope I don't want to add noise.

Mike

>
> On Wed, Jan 20, 2021 at 2:56 PM Murray S. Kucherawy 
> <superuser@gmail.com <mailto:superuser@gmail.com>> wrote:
>
>     On Wed, Jan 20, 2021 at 1:21 PM Michael Thomas <mike@mtcc.com
>     <mailto:mike@mtcc.com>> wrote:
>
>         I just scanned through DMARC and I couldn't find any security
>         requirements/mechanisms for the failure reports. I would think
>         at the
>         very least the receiver consuming the reports ought make
>         certain that
>         the report at the very least have either a valid DKIM
>         signature or a SPF
>         pass. Unauthenticated data is always the source of mischief,
>         and I'm
>         sure that there have to be attacks that are possible with
>         unauthenticated reports. At the very least this should be a
>         security
>         consideration, and most likely should have some normative
>         language to
>         back it up.
>
>
>     I thought the usual rules about when you should or shouldn't trust
>     a message ought to be applied, but I guess we never actually said
>     that in the document.  We certainly could.
>
>         Since I'm sort of new, it's been unclear to me whether whether
>         having a
>         new https transport mechanism is in scope or not -- it seems
>         to come up
>         pretty often -- but I'm not sure how people would propose to
>         authenticate the report sending client. That seems to me to be
>         a basic
>         security requirement for any new delivery method. The problem
>         here is
>         there isn't a client certificate to determine where the report
>         is coming
>         from or any other identifying mechanism. An alternative might
>         be to DKIM
>         sign the report itself, but the long and short is that it
>         would need to
>         be addressed.
>
>
>     As I recall DMARC originally (in its pre-RFC versions) did have
>     "https" as a supported scheme for "rua", but since nobody
>     implemented it during the years DMARC was in development, it got
>     dropped before publication.
>
>     -MSK
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>
>
> -- 
> *Seth Blank*| VP, Standards and New Technologies
> *e:*seth@valimail.com <mailto:seth@valimail.com>
> *p:*415.273.8818
>
>
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