Re: Mailing list and Gcc header in nnimap groups

["Matt Armstrong" <matt+dated+1007925301.f1c199@lickey.com>]

Amos Gouaux <amos+lists.ding@utdallas.edu> writes:

>>>>>> On Fri, 09 Nov 2001 17:50:46 +0100,
>>>>>> Kai Großjohann <Kai.Grossjohann@CS.Uni-Dortmund.DE> (kg) writes:
>
> kg> Suppose I've got an nnimap group for a mailing list and compose a
> kg> message to the list.  The message has a Gcc header pointing to that
> kg> group (via gcc-self).
>
> [...]
>
> kg> Using Cyrus 1.6.22.
>
> Hmmm... is duplicate delivery check enabled on the Cyrus server?  I
> think it uses the Message-ID for this check.  Perhaps this would
> take care of the dups for you??

Duplicate suppression by Message-ID is insecure:

    - You send a mail to Bob and Patty

    - Patty gets your mail, manages to disrupt Bob's mail delivery and
      sends a message to Bob with the same Message-ID.

    - Bob gets Patty's mail first.

    - Bob's Message-ID duplicate suppression system deletes your mail
      when it finally arrives.

Of course, I don't think this is a problem in practice.  But it is
safer to suppress duplicates based on checksums of the message
contents.

-- 
matt