Re: [ietf-822] one can re-sign without a permission to re-sign header

[Paul Smith <[e-mail]>]

On 02/05/2014 15:42, John R Levine wrote:
>> I don't see any replay protection in here at all. Nothing that says 
>> to keep the signature expiration relatively short, and nothing which 
>> a mailing list recipient could not subsequently use to send spam. The 
>> first issue just needs a mention. It's the second issue that needs to 
>> be addressed IMO:
>
> Yeah, that occurred to me about five minutes after I posted it. Here's 
> a tweaked version where the mf tag is now mf=list.domain, with 
> handwaving about how a may-forward signature doesn't count unless 
> there's also a signature from the list domain.  Given lengthy 
> discussions about how little abuse comes from real mailing lists, 
> that'd probably be adequate.
>
> http://datatracker.ietf.org/doc/draft-levine-may-forward/
Could this be 'extended' to include message-ids in the MF signature?

That would provide some replay protection, especially if the forwarder 
checks for duplicate message-ids (the recipient could also check for 
dupes). Without it, I could see one of your messages on a list, then 
send messages to everyone on the list, pretending to be you.



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