On 11/29/2017 03:00 PM, Grant Taylor via NANOG wrote:
On 11/29/2017 03:46 PM, Michael Thomas wrote:
You know what the original header was via the signature. You can take
the delta of the current subject line and remove any additions and
validate the signature. Whether you're happy with the additions is a
different concern,
Are you referring to the optional z DKIM-Signature tag?
Or are you referring to brute forcing what the subject was in order to
derive the delta of the current subject? This would be compounded by
any number of other changes to (over)singed headers / body portion.
If I were constructing a spam filter out of it, I'd give a lot of
prejudice to anything added, but that's outside of
what you can do within the bounds of the spec.
*If* the z tag was included in the DKIM-Signature header, I can see
how this would work and I agree with your distrust of said additions /
alterations.
Yes, with the z=
Mike
