[Mailman-Users] Major problems with privacy and mailman lists and harvesters

Steve Murphy murf at digium.com
Fri May 23 19:03:20 CEST 2008


I'm quite concerned about what I'm seeing in mailman installations,
and the amount of spam I've been getting because I participate in
mailman based lists!

I'm not talking about halting spam that gets submitted to the list
for mailing. I'm not talking about spambots automatically joining
the lists and submitting spam. 

What I'm concerned about is the fact that email harvesters are being
given so much information.

I've noticed in the mailman-users archives, that if I view info 
by thread (using the mailman archives as an example,) 
which site is 2.1.10 based,
that all email addresses are present, but with a simple obfuscation.
(the "@" has been changed to " at ".) I can't help but to think
that this simple obfuscation is a joke. Any harvester written in the
past number of years would be smart enough to capture such accurately.

When viewing the developer's archives, I note that when a message is
displayed singly, it is common to see [EMAIL PROTECTED]. This is
much nicer, but I notice that in both archives, a button is provided
at the bottom of the letter, that submits a form, and gets back 
both a "Found" page, with a mailto: url, and a redirect to a mailto... 
so, an anonymous user can easily get/harvest email addresses by simply 
analyzing the html form.

The gzip'd archives by month for both lists both show all email
addresses, with the " at " obfuscation.

It seems inconsistent, funny even, that display by thread will show
individual messages with [EMAIL REMOVED], but the gzip'd archives
of the same message reveal, really, everything.

And worse... If I really wanted to collect up-to-date juicy email
addresses, I'd simply subscribe to all the mailman lists I possibly
could, and
route all the incoming messages to harvesters. In **This** case,
the harvest is bountiful, as most messages arrive totally unfiltered,
from  headers galore bearing bounteous harvests of email addresses
(for example, the From header), to the user sigs at the ends, with
reply quotation headers mentioning the source addresses in between.

Within MINUTES of my first posting on asterisk-users, I was getting spam
on an email address that was brand-new. Since then, the spam volume
on that email addr just keeps growing.

I keep wondering, which way did they get my email addr? 
But, it doesn't matter. I can't help to think that 'targeted'
spam mailers both spider the archives and subscribe to the
lists.The bigger the list's subscription, hotter an item it is.

So, please, can we apply the [EMAIL PROTECTED] tech to the archives,
and the outgoing messages, and drop this silly notion that 
the " at " obfuscation is useful? Really, it's totally transparent. 
NO OBFUSCATION is safe in mailman. There's simply too much 
Can we drop the buttons from the archives whose HTML says:

<FORM METHOD="POST" ACTION="/cgi-bin/Nomailto.pl">
<INPUT TYPE="HIDDEN" NAME="host" VALUE="nleaudiox.com">
<INPUT TYPE="HIDDEN" NAME="subject" VALUE="Re: [Mailman-Developers] Important Mailman 2.1.9 to 2.1.10 upgrade note.">
<INPUT TYPE="HIDDEN" NAME="msgid" VALUE="480E15F1.50200 at nleaudio.com">
Reply via email to<br>

from which spam harvesters can almost instantly be updated to harvest "barb at nleaudiox.com"
(modified from the orig to save the innocent author from a deluge of spam, at
least on **my** account), without even submitting the form!

We need to rethink how we can adequately keep emails out of spammers hands.
And, yes, it's kinda unhandy not read a message and not be able to fire an email
off to the author directly. But to make it easy for list subscribers, is to make it easy
for spammers, who probably have already joined the list, and are delighted
to get email addresses, any which way they can.

Most discussion on mailing lists do not require any address other than
the the mailing list itself. To take a discussion "offline", I propose a
few ideas: 

1. the mailing list allows the users to specify a phone-number,
an irc channel and identity that they can be reached by, or some other
method to contact the author, that is NOT an email address. This info
is kept private, and the button at the bottom of the archived letters
could give you this info. The person wanting to privately discuss the
letter could then call the user or contact them via irc/jabber/whatever,
and either discuss the matter there and then, or the author could
voluntarily give the other party his email address at that time. Or
file a list message, and ask the author to contact him, and give out a 
phone number, whatever.

I thought about integrating spamgourmet throw-away email addresses,
but really, that wouldn't help. Spammers could simply request, get
the throw-away, spam it, and toss it. The user himself is the only
one who can usefully hand out throw-away addresses.

If you think mailman doesn't have to worry about this sort of thing,
keep in mind that mailman has swiftly become probably the top mailing
list software on the web. That spammers would not be interested in
mining mailing lists for their tens of thousands of valid addresses
is foolhardy thinking. That thinking the options that mailman provides
now is adequate to keep spammers from harvesting email addrs, is just
plain wrong. That datamining and de-obfuscation are NOT being done
for mailman lists is wishful thinking.

Mailman needs to pay attention to the fact that spammers would **love**
to use their mailing list installations to ship spam for them, AND ALSO
that spammers will want to harvest email addresses from the web
AND the mailings themselves. 

We need to lock down mailman, or at least make it an option! Simply put,
in messages sent to users, the only email that should be found anywhere
in a recieved message, is the recipient's.
In the archived messages, absolutely no email addresses at all. Not even
obfuscated. If we follow this pattern, the spammers will not be able to
use mailman lists for any useful purpose. They'll have to hack the web
to get the lists.


Steve Murphy
Software Developer

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