-----Original Message-----
From: ietf-dkim-bounces(_at_)mipassoc(_dot_)org
[mailto:ietf-dkim-bounces(_at_)mipassoc(_dot_)org] On Behalf Of Steve Atkins
Sent: Monday, October 25, 2010 12:54 PM
To: IETF DKIM WG
Subject: Re: [ietf-dkim] Proposal for new text about multiple header issues
I'd strike "during a replay attack" because, as some have noted, the
attack can be constructed deliberately on an original message.
The real risk here is that someone can present a message as signed by
someone trustworthy that has content different to that which was
provided by the trusted signer. If the entity adding the additional
content is the original signer, it may be a message composition bug,
but it's not really any sort of attack on DKIM.
Striking "replay attack" might make it less clear what the actual risk
is, rather than more clear.
("... can be abused, e.g. during a replay attack, by adding ..." ?)
Isn't the more interesting attack a signature from some throwaway domain that
covered a matching From: but also contained a From: indicating some high-value
phish target?
It's also not specific to MUAs. Filtering agents can be similarly
duped.
They can, yes, though I'm not sure that's needed to explain why this
may be a bad thing to allow.
Focusing on the MUA case might inadvertently suggest to implementers of other
components that this is not a concern for them.
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