Leon Rothenberg wrote:
> The only solution I can think of off the
> top of my head is to make the ":include:" alias something cryptic, so
> that potential spammers would have trouble guessing it:
>
> test: "|/usr/test/majordomo-1.94.3/wrapper resend -l test
> test-zzoutgo898"
> test-zzoutgo898: :include:/usr/test/majordomo-1.94.3/lists/test
>
> Are we missing something obvious here?
Section 3.6 of the FAQ discusses this problem in depth. One thing you
may be missing is that, depending on how your MTA is configured, it can
be very easy for a spammer to discover the "cryptic" outgoing alias by
means of the EXPN and/or VRFY SMTP commands:
% telnet yourhost smtp
...
vrfy test
250 <"|/usr/test/majordomo-1.94.3/wrapper resend -l test test-zzoutgo898"@yourhost>
expn test
250 <"|/usr/test/majordomo-1.94.3/wrapper resend -l test test-zzoutgo898"@yourhost>
You may be be able to defend against this by configuring your MTA to
refuse EXPN and VRFY for the list address, or by configuring it to
refuse externally-generated mail for the outgoing alias.
It's also possible that your MTA will "leak" the name of the outgoing
alias by pasting it into a Received header in the outbound message.
I suggest that before anyone else chimes in on this thread they at least
review the FAQ to make sure that they're not just rehashing old
information: <http://www.greatcircle.com/majordomo/majordomo-faq.html#3.6>
Regards, Mike.
--
mike.oliver@eng.sun.com
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