-dkim] ISSUE: 4871bis - Security Loop hole with
Multiple 5322.From
And note that pious exhortations to ensure that RFC5322 be followed, or
that MUAs should be fixed to solve this problem, are no solution. We
live
in the Real World (TM), and neither of those things is going to happen
-Original Message-
From: ietf-dkim-boun...@mipassoc.org [mailto:ietf-dkim-boun...@mipassoc.org]
On Behalf Of Charles Lindsey
Sent: Thursday, October 07, 2010 3:29 AM
To: DKIM
Subject: Re: [ietf-dkim] ISSUE: 4871bis - Security Loop hole with Multiple
5322.From
If we can't rely
On Mon, 04 Oct 2010 23:24:11 +0100, Hector Santos hsan...@isdg.net wrote:
I propose the following addition text by adding to 48721bis to address
this serious issue;
Special Consideration for Verifying and Signing From: Header
As an exception, header hash verification MUST be done for
-Original Message-
From: ietf-dkim-boun...@mipassoc.org [mailto:ietf-dkim-boun...@mipassoc.org]
On Behalf Of Charles Lindsey
Sent: Wednesday, October 06, 2010 3:47 AM
To: DKIM
Subject: Re: [ietf-dkim] ISSUE: 4871bis - Security Loop hole with Multiple
5322.From
And note
--On 4 October 2010 18:24:11 -0400 Hector Santos hsan...@isdg.net wrote:
It has been observed by implementations that is it possible to replay
a message with a 2nd 5322.From header at the top which wouldn't break
the DKIM signature validity, but would often be displayed by MUAs to
display
On 10/5/2010 8:15 AM, Ian Eiloart wrote:
It has been observed by implementations that is it possible to replay
a message with a 2nd 5322.From header at the top which wouldn't break
the DKIM signature validity, but would often be displayed by MUAs to
display the new 5322.From display
To: Hector Santos; ietf-dkim@mipassoc.org
Cc: Tim Polk
Subject: Re: [ietf-dkim] ISSUE: 4871bis - Security Loop hole with Multiple
5322.From
It has been observed by implementations that is it possible to replay
a message with a 2nd 5322.From header at the top which wouldn't break
the DKIM
Hector Santos wrote:
It has been observed by implementations that is it possible to replay
a message with a 2nd 5322.From header at the top which wouldn't break
the DKIM signature validity, but would often be displayed by MUAs to
display the new 5322.From display rather than the signature
Julian Mehnle wrote:
Hector Santos wrote:
It has been observed by implementations that is it possible to replay
a message with a 2nd 5322.From header at the top which wouldn't break
the DKIM signature validity, but would often be displayed by MUAs to
display the new 5322.From display rather
On 10/5/10 8:45 AM, Dave CROCKER wrote:
At a deeper level, there is a continuing problem with casting DKIM as a
mechanism to protect a message. That's something that OpenPGP and S/Mime
do;
it's not something DKIM does. DKIM merely tries to do enough to ensure that
the
d= is valid, to
-Original Message-
From: ietf-dkim-boun...@mipassoc.org [mailto:ietf-dkim-boun...@mipassoc.org]
On Behalf Of Julian Mehnle
Sent: Tuesday, October 05, 2010 7:27 AM
To: ietf-dkim@mipassoc.org
Subject: Re: [ietf-dkim] ISSUE: 4871bis - Security Loop hole with Multiple
5322.From
Ian Eiloart wrote:
--On 4 October 2010 18:24:11 -0400 Hector Santos hsan...@isdg.net wrote:
It has been observed by implementations that is it possible to replay
a message with a 2nd 5322.From header at the top which wouldn't break
the DKIM signature validity, but would often be
Murray S. Kucherawy wrote:
But the attacker in this scenario is already the signer (or has
compromised the signer), so he/she will just sign the single From:.
If the attacker is the signer, they can just as well resign many times.
I don't think that's the scenario that Hector meant, though.
-Original Message-
From: ietf-dkim-boun...@mipassoc.org [mailto:ietf-dkim-boun...@mipassoc.org]
On Behalf Of Julian Mehnle
Sent: Tuesday, October 05, 2010 9:28 AM
To: ietf-dkim@mipassoc.org
Subject: Re: [ietf-dkim] ISSUE: 4871bis - Security Loop hole with Multiple
5322.From
Please don't CC me. I'm subscribed to the list.
Hector Santos wrote:
Julian Mehnle wrote:
The trick is to list From twice in h=. This ensures more From headers
cannot be added without breaking the signature.
Julian, this was explored and it does not matter. You can add N
number of
Comments inline
-Original Message-
From: ietf-dkim-boun...@mipassoc.org [mailto:ietf-dkim-
boun...@mipassoc.org] On Behalf Of Dave CROCKER
Sent: Tuesday, October 05, 2010 8:45 AM
To: Ian Eiloart
Cc: Tim Polk; ietf-dkim@mipassoc.org
Subject: Re: [ietf-dkim] ISSUE: 4871bis - Security
Dave CROCKER d...@dcrocker.net wrote:
On 10/5/2010 8:15 AM, Ian Eiloart wrote:
It has been observed by implementations that is it possible to replay
a message with a 2nd 5322.From header at the top which wouldn't break
the DKIM signature validity, but would often be displayed by MUAs to
-Original Message-
From: ietf-dkim-boun...@mipassoc.org [mailto:ietf-dkim-boun...@mipassoc.org]
On Behalf Of Scott Kitterman
Sent: Tuesday, October 05, 2010 12:24 PM
To: ietf-dkim@mipassoc.org
Subject: Re: [ietf-dkim] ISSUE: 4871bis - Security Loop hole with Multiple
5322.From
It has been observed by implementations that is it possible to replay
a message with a 2nd 5322.From header at the top ...
A thing with two From: headers isn't a valid RFC 5322 message.
You may recall a lengthy argument about what to do with messages with
bare carriage returns, with the final
Julian Mehnle wrote:
Hector Santos wrote:
Julian Mehnle wrote:
The trick is to list From twice in h=. This ensures more From headers
cannot be added without breaking the signature.
Julian, this was explored and it does not matter. You can add N
number of h=from: and N+1 is all that is
Hector Santos wrote:
Julian Mehnle wrote:
I interpret RFC 4871, section 5.4 (actually, exactly the part you
quoted originally), such that signing a message that has a dingle
From field with h=From:From ensures that adding another From field
will break the signature. If you're saying
- Security Loop hole with Multiple
5322.From
Nack. DKIM also purports to provide assurance that the signed content
of the message is unmodified. I think mentioning that all instances of
a header that is signed should be used for signing and verification is
a useful data point for implementors
It has been observed by implementations that is it possible to replay
a message with a 2nd 5322.From header at the top which wouldn't break
the DKIM signature validity, but would often be displayed by MUAs to
display the new 5322.From display rather than the signature bound
5322.From header.
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