[Mailman-Users] bots subscribing to lists via web forms to avoid member-only restrictions

[Matt Domsch]

Several times this week I've received spam to my lists which are set
to allow postings only by list members.  Upon review, something
(either bot or human, but I'm betting bot as they hit many lists at
once) subscribed the spam sender email to the lists via the web form,
sent the spam, then unsubscribed themselves.

The actual spam message was declared clean by both SpamAssassin and
IronPort, so the filtering ahead of MM is quite helpful, but not perfect.

Are there plans to enhance the web subscription form with a type of
captcha, or other technique to discourage bots?

Anyone else hit by this practice much?

Thanks,
Matt
http://lists.us.dell.com list admin

-- 
Matt Domsch
Linux Technology Strategist, Dell Office of the CTO
linux.dell.com & www.dell.com/linux