[Mailman-Developers] MTA load, custom messages, bounces

[Peter W]

On Fri, Dec 07, 2001 at 06:40:15PM -0800, Peter C. Norton wrote:
> On Fri, Dec 07, 2001 at 02:36:39PM -0500, Peter W wrote:

> > How robust is the bounce detection? Even with VERP and/or good MTAs,
> > is there enough smarts in the system to prevent a black hat from connecting 
> > to the MTA on the mailman server and using fake bounce messages to
> > knock someone off a list without their knowledge? 
> 
> You can avoid this by is by sending a test message to them and use a cookie
> in the envelope-from that is a hash of a saved secret value that you can
> compare to on the bounce.

Right. That's what I'm suggesting, that maybe such a cookie plan should be
implemented. I like my idea of the cookie being a hash of both the
recipient address and something like a time value, so that "replay"  
attacks are less feasible. You shouldn't be able to pick up a disk drive
that Barry W discarded a year earlier and get a cookie that still lets you
unsubscribe him from this list. :-)

>  If you get a bounce to the address that has the
> proper hash, then you can pretty safely disable them (unless their
> postmaster is out to get them.  But you can't save them from that).

Or if someone gets to their saved messages, right.

>  If you
> don't get the message bounced back then that email address isn't really (or
> at least always) bouncing.

Eaxctly. Sounds like we're in basic agrement about the potential value of 
a cookie-laden envelope?

-Peter

-- 
I am what I am 'cause I ain't what I used to be. - S Bruton & J Fleming