----- Original Message -----
From: "Wietse Venema" <[EMAIL PROTECTED]>
To: <ietf-dkim@mipassoc.org>
Sent: Tuesday, September 12, 2006 12:22 PM
Subject: Re: [ietf-dkim] SSP = FAILURE DETECTION
>>>What was the advantage of SSP with look-alike domains?
>>>
>> To find large unproductive ratholes? Neither DKIM or SSP claim
>> to have any direct effect on look-alike domain names, and
>> there's nothing in our
>
> DKIM_BASE allows a recipient to distinguish mail from the bank from
> look-alike mail that pretends to be from the bank. That information
> comes in the form of the signing domain.
>
> SSP has an advantage when we assume that criminals are stupid enough
> to keep sending forged mail. It has no advantage with look-alike
> attacks. Guess what criminals will do.
hmmmmmmmmm, unless I didn't follow you right, I fail to see the distinction
or your point.
Scenario #1 - No Phishing in 2822.From, Phishing in signing domain. NO SSP
defined.
From: [EMAIL PROTECTED]
To: [EMAIL PROTECTED]
Subject: Your Account Info
DKIM-Signature: d=paypa1.com; s=sept06; <-- valid 3PS
Here, the 3PS is valid using a look-alike domain (character one is used
instead of el). The x822.From is really paypal.com and no SSP is defined.
The result in a NO SSP enviroment is a VALID message with the awful
possibility some stupid Presentatation software will say:
* Good Signature from [EMAIL PROTECTED] signed by
paypa1.com
Scenario #2 - Phishing in 2822.From, Phishing in signing domain.
From: [EMAIL PROTECTED]
To: [EMAIL PROTECTED]
Subject: Your Account Info
DKIM-Signature: d=paypa1.com; s=sept06; <-- valid 3PS
Here, the 3PS is valid using a look-alike domain (character one is used
instead of el). The x822.From is also phished. The bad guy can have NO SSP
or a SSP with an designated allow list for paypa1.com
So I don't see the how it matters.
But I will say that if PAYPAL.COM (the real domain) used SSP in scenario #1,
then at the very least, the real domain is protected against a phished
signing domain when using SSP. So to me, SSP still has the advantage over a
DKIM-BASE only environment.
SSP can protect against a PHISHED DKIM-BASE SIGNATURE. A slight
distinction over a phished 2822.From domain. In short, the bad guy would
have to phish both domains - the authors and the signing domain.
--
Hector Santos, Santronics Software, Inc.
http://www.santronics.com
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