[ale] Gmail accepts spam when you use email forwarding

[Brandon Checketts]

This is a weakness of SPF, and why Google, Yahoo, and others are
championing DKIM.

Also, remember that attempts at sender validation (ie: SPF and DKIM)
don't indicate whether a message is spam or not (spammers can use them
too).  It just makes it possible to build a reputation based on the
sender address.

Thanks,
Brandon Checketts



Jim Popovitch wrote:
>>From Google's perspective, Line 08 could always be spoofed so Google
> only relies on what Google knows to be true.
> 
> -Jim P.
> 
> On 2009-12-15, Richard Bronosky <Richard at bronosky.com> wrote:
>> Let me know if Google is in the wrong, or I am crazy.
>> What I have is a postfix server on slicehost that I use solely for the
>> purpose setting up @bronosky.com email forwarders for members of my
>> family, and as an outgoing mail server (which I have Gmail using!).
>> Most of us are using Gmail now, but some of the stragglers are still
>> on Hotmail or Yahoo!. For the past week 15 times a day I have been
>> receiving and reporting as spam the same message (nearly) with very
>> similar heads.
>>
>> line01: Delivered-To: richardbronosky at gmail.com
>> line02: Received: by 10.220.108.106 with SMTP id e42cs49574vcp; Tue,
>> 15 Dec 2009 00:24:04 -0800 (PST)
>> line03: Received: by 10.216.90.196 with SMTP id
>> e46mr2408469wef.194.1260865444149; Tue, 15 Dec 2009 00:24:04 -0800
>> (PST)
>> line04: Return-Path: <nmike at bronosky.com>
>> line05: Received: from slice1.bronosky.com (slice1.bronosky.com
>> [174.143.204.116]) by mx.google.com with ESMTP id
>> t12si19704611gvd.5.2009.12.15.00.24.02; Tue, 15 Dec 2009 00:24:03
>> -0800 (PST)
>> line06: Received-SPF: pass (google.com: best guess record for domain
>> of nmike at bronosky.com designates 174.143.204.116 as permitted sender)
>> client-ip=174.143.204.116;
>> line07: Authentication-Results: mx.google.com; spf=pass (google.com:
>> best guess record for domain of nmike at bronosky.com designates
>> 174.143.204.116 as permitted sender) smtp.mail=nmike at bronosky.com
>> line08: Received: from alixpartners.com (unknown [116.68.243.172]) by
>> slice1.bronosky.com (Postfix) with SMTP id 6D0A017643 for
>> <deadmail at bronosky.com>; Tue, 15 Dec 2009 08:26:44 +0000 (UTC)
>> line09: From: VIAGRA ® Reseller <deadmail at bronosky.com>
>> line10: To: deadmail at bronosky.com
>> line11: Subject: Deal of the Day: Save 76%
>> line12: MIME-Version: 1.0
>> line13: Content-Type: text/html; charset="ISO-8859-1"
>> line14: Content-Transfer-Encoding: 7bit
>> line15: Message-Id: <20091215082645.6D0A017643 at slice1.bronosky.com>
>> line16: Date: Tue, 15 Dec 2009 08:26:44 +0000 (UTC)
>>
>> the part that really sucks are line06 and line07. All mail for
>> @bronosky.com is going to come to Google forwarded from
>> slice1.bronosky.com because that's the way it is. Where I believe
>> Google is goofing up is that they are SPF checking the IP from line05
>> instead of the IP from line08. So, the trick to spamming any Gmail
>> user who forwards from another domain is the set the From: header to
>> an address @ that domain. Seems like a huge fail to me.
>>
>> Please opine.
>>
>> --
>> .!# RichardBronosky #!.
>>
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> 
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