Re: [dmarc-ietf] Recipient domain in aggregate reports (#23)

"Murray S. Kucherawy" <superuser@gmail.com> Tue, 04 May 2021 00:14 UTC

Return-Path: <superuser@gmail.com>
X-Original-To: dmarc@ietfa.amsl.com
Delivered-To: dmarc@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id B34753A1A59 for <dmarc@ietfa.amsl.com>; Mon, 3 May 2021 17:14:09 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -2.097
X-Spam-Level:
X-Spam-Status: No, score=-2.097 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, FREEMAIL_FROM=0.001, HTML_MESSAGE=0.001, RCVD_IN_DNSWL_BLOCKED=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001] autolearn=ham autolearn_force=no
Authentication-Results: ietfa.amsl.com (amavisd-new); dkim=pass (2048-bit key) header.d=gmail.com
Received: from mail.ietf.org ([4.31.198.44]) by localhost (ietfa.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id s6Z1qs9Nk9Cm for <dmarc@ietfa.amsl.com>; Mon, 3 May 2021 17:14:04 -0700 (PDT)
Received: from mail-ua1-x92a.google.com (mail-ua1-x92a.google.com [IPv6:2607:f8b0:4864:20::92a]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id 74B9D3A1A55 for <dmarc@ietf.org>; Mon, 3 May 2021 17:14:04 -0700 (PDT)
Received: by mail-ua1-x92a.google.com with SMTP id u15so2500675ual.9 for <dmarc@ietf.org>; Mon, 03 May 2021 17:14:04 -0700 (PDT)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=53F3j8F/6Livigntgyhts4Z39WkExYatC2xeegu3p6Q=; b=P3S8LTJu/KlJQrv5mOCb4EFRRI9N4yE2SMBhVduiM70txmSSKXl5Ujw9bqwGm/ybqo V2yc48zTOawQHLCmp/iDanfGaAZb4LP7zeKywcYG/I6rZ/nJy8LV1dLs5NW4B4UiCfgh L1dYDovqpdg0dQwOV/VExkYx1gBGHtAlIHpTFuUuuJgM4rHjP9ypdkAMgfooLZFo0cBW QVVT58Tu0CJbSZ+wqKfduaYXbNgB1N5MGQ4s++DIBUz3vZ3F9nKPy4k6gCSyDenlsZn7 GghCzvNlEujYQ8CZ/hu/Z/hz4bKO5L2D2RsXvbf5YTlqyLBkXMdXvifiXpA+TmT44T3r rqKQ==
X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=53F3j8F/6Livigntgyhts4Z39WkExYatC2xeegu3p6Q=; b=BQ90hMUFdtoSxY4ytzR3uWBGTIpPya10T/c/bR88mx+UrJRzTqIGkSqYZ4VVR6OmAb t4ayWlpuCE3HNfV07Y9sOyurAiKnqIxhiAcU5DbuTCOsA1xZEn5CCfGnsSV6n19CGz6o y7Gsgci3mKDeQ8/NlBrOMhDqeRwatY4GWzgME3DtgH2SUjKU1JTGix5cM6LkNP8p1Nym H+ThkTo8/UtH9keGNuyu6ViFuLizjs8pe6HbCxZ9vtkYe06LIoB8EUrpFN9gZrPpgd2D iJ6fLqz7SYhW5d1NueVzT1Z8AMGuFFCUjfc6JUeWRt2ZxsU731yLmWvRo6mvHFBR2rhT PNPA==
X-Gm-Message-State: AOAM531FViBjNPV9AKXCSasuKP6WyePGetDcLhuS+hEOxzo93XzxCeqQ 55Wyu/iW59b6+KOVJFSW6aftn6CIw0CggUt4G6A=
X-Google-Smtp-Source: ABdhPJw+24ioBq4UY746lCmGm+O7IHx/iPtfJKTYFktPvwLp7Sx/6zBjnQcXA9sTSrTKyBsQ0w/1WsBnum4yc+j+mVU=
X-Received: by 2002:ab0:4757:: with SMTP id i23mr18350170uac.87.1620087242988; Mon, 03 May 2021 17:14:02 -0700 (PDT)
MIME-Version: 1.0
References: <20210502203007.2AE156284F0@ary.qy> <215690a6-2b04-3355-9999-816a1c3d7126@heeg.de> <70E22447-47F6-4B92-B47F-664A81107836@wordtothewise.com> <CAH48Zfy0_jvDAtwQ+MrK4kk=J1iqO=6z1+ToBPiAOYeJ5qWHyg@mail.gmail.com> <692CBE21-4222-4353-8D03-EE4B287405EF@wordtothewise.com> <CAH48ZfzH24kw9Rn8t_r-WmsBVQKcrNnV9Px0Gr7ufJcSncmUuQ@mail.gmail.com>
In-Reply-To: <CAH48ZfzH24kw9Rn8t_r-WmsBVQKcrNnV9Px0Gr7ufJcSncmUuQ@mail.gmail.com>
From: "Murray S. Kucherawy" <superuser@gmail.com>
Date: Mon, 3 May 2021 17:13:51 -0700
Message-ID: <CAL0qLwYRkrVQ3cH0zWxfV1nvzArzEkq859SMdaYH1pFRwVW5wQ@mail.gmail.com>
To: Douglas Foster <dougfoster.emailstandards@gmail.com>
Cc: IETF DMARC WG <dmarc@ietf.org>
Content-Type: multipart/alternative; boundary="0000000000009fa17405c175f416"
Archived-At: <https://mailarchive.ietf.org/arch/msg/dmarc/fXFlynob6rY1Ypvi62dMHA44gP8>
Subject: Re: [dmarc-ietf] Recipient domain in aggregate reports (#23)
X-BeenThere: dmarc@ietf.org
X-Mailman-Version: 2.1.29
Precedence: list
List-Id: "Domain-based Message Authentication, Reporting, and Compliance \(DMARC\)" <dmarc.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/dmarc>, <mailto:dmarc-request@ietf.org?subject=unsubscribe>
List-Archive: <https://mailarchive.ietf.org/arch/browse/dmarc/>
List-Post: <mailto:dmarc@ietf.org>
List-Help: <mailto:dmarc-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/dmarc>, <mailto:dmarc-request@ietf.org?subject=subscribe>
X-List-Received-Date: Tue, 04 May 2021 00:14:10 -0000

On Mon, May 3, 2021 at 5:26 AM Douglas Foster <
dougfoster.emailstandards@gmail.com> wrote:

> I meant to say that we need N unique (and valid) smtp TO addresses, so
> that an attacker cannot send a single email address and wait for an rua
> report to know where it lands.
>
> Valid addresses are needed to hinder usage of bogus addresses to defeat
> the test.
>

Is that enough?  If I control a domain, I can make up any number of
apparently-valid envelope addresses I want.

Using DKIM selectors for tracking will also put a huge load on DNS if
> implemented at scale [...]
>

How so?

-MSK