[Mailman-Users] Spoofing Issue

[texas critter - mailman-users]

Thomas Hochstein wrote:

> Of course. Mailman - as most or all other MLAs - only checks the
> From:-Header; that means, "spoofing" is as easy as entering your mail
> address (or the mail address of someone who is allowed to send mail to
> the list) as the sender.

FYI, Mailman actually checks more than the From header which is how the
Beagle virus is able to post to lists.  Beagle forges the Envelope-From and
Mailman alsoe checks that header for member addresses and their posting
privileges so if Beagle happens to get a valid list member who's not
moderated in the Envelope-From header, the message goes thru to the list
(happened to me at the beginning of February on a list of 1,200 plus
members).  The Envelope-From is then stripped when Mailman processes the
message and sends it back out to the list.

You can set Mailman to only check the From header by putting this line in
your mm_cfg.py file:

SENDER_HEADERS = ('from')

Mailman's Default.py shows what headers it checks by default.

hth,
texas critter

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