[Mailman-Users] Mail Lists, Authorized Posters and Virus/Worm Access

Lloyd Tennison lloyd_tennison at whoever.com
Wed May 5 11:46:40 CEST 2004

Set the mm_cfg.py and see Default.py for this info:

# The envelope sender is set by the SMTP delivery and is thus less easily
# spoofed than the sender, which is typically just taken from the From: header
# and thus easily spoofed by the end-user.  However, sometimes the envelope
# sender isn't set correctly and this will manifest itself by postings being
# held for approval even if they appear to come from a list member.  If you
# are having this problem, set this variable to No, but understand that some
# spoofed messages may get through.

This will help block some of your problem - unauthorized posts.  The virus checker still goes.

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>From: Richard Barrett <r.barrett at openinfo.co.uk>
>Subject: Re: [Mailman-Users]  Mail Lists,
>	Authorized Posters and Virus/Worm Access
>Date: Wed, 5 May 2004 10:37:21 +0100
>To: Bob Bowers <b-bowers at cox.net>
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>On 5 May 2004, at 09:28, Bob Bowers wrote:
>> In my community last week, someone gained access to a mail list with 
>> hundreds of subscribers by mimicking an email address authorized to 
>> post to the list (moderation bit set OFF). In such a case, moderator 
>> approval was not required. What resulted was that a worm of the 
>> W32Beagle variety was sent to many hundreds of subscribers. I have 
>> changed all my mail lists to require active moderation of all posts 
>> (moderation bits are ON for all subscribers), and automatic rejection 
>> of all posts from non-members.
>> It appears that it was just a matter of time for someone with ill 
>> intent to figure out that the "from" address in a message from a mail 
>> list might represent access to the mail list for mischief. It would 
>> not appear accidental that a virus or worm operating on some 
>> unsuspecting individual's computer accidentally sent itself to the 
>> posting address of a mail list as well as from an authorized email 
>> address. It is more likely that it was deliberate.
>I doubt that the virus writer was targeting mailing lists in this 
>considered fashion; to them, a mail alias is just a mail alias.
>I understand these virus types use the MUA address book on machines it 
>infects as a source of mail address to send its progeny on to. One of 
>your list's subscribers was probably the source of the infected message 
>and your list's address just one of a number pillaged from that user's 
>address book as destinations by a promiscuous virus.
>In my view, running effective virus (and spam) filtering on your 
>incoming MTA is the secret of happiness. It keeps viruses away from 
>your both your lists' and your real users' mail aliases, and it means 
>you do not have to moderate everything if the virus loaded messages are 
>being silently dropped in the bit bucket by the MTA.
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