Firewall Wizards mailing list archives

Re: sendmail spamming


From: "Robert E. Martin" <rmartin () fishburne org>
Date: Thu, 29 May 2003 12:35:29 -0400

Behm, Jeffrey L. wrote:

Morality? Is that old thing still around? ;-)

If I understand your question correctly, the gain is that the real spammer
is using your web server to generate SPAM and making it look as if your web
server is the real spammer (The real spammer has little risk in being
labeled a "SPAMMER" from the Internet-at-large). It's just a way for a real
spammer to cover his/her tracks and cause your site grief, because *you* now
are at risk of being labeled a "SPAM-generating" site. To the recipient of
such spam, the "from" address is legitimately from your web server. However,
the exploit isn't really your email server, it's the web server <I hope
you're not gonna say you have a web server on the *same* system as your
email gateway :-(  >. The web server legitimately uses the email gateway to
send emails out to the internet, but the web server has been exploited to
allow the intruder to send out emails which are tracked back to "coming from
the web server."

Hope this helps, and that I understood your question correctly.
Jeff

-----Original Message-----
From: Robert E. Martin [mailto:rmartin () fishburne org] Sent: Thursday, May 29, 2003 8:31 AM
To: firewall-wizards () honor icsalabs com
Subject: [fw-wiz] sendmail spamming


Just a moraltiy question for you guys.
I have just finished locking up and exploit in our email server. This spawned from a formmail script left on our web server I neglected to delete. I noticed CPU activity spikes on the email server and found that our web server was spamming our email server due to the classic formmail exploit. My question is this. What is the motivation behind such an expliot? What is there to gain from this other than job security for a person like me? This kind of action makes no sense to me.

--
Robert E Martin
IT Manager
Fishburne Military School
rmartin () fishburne org
540.946.7726
_______________________________________________
firewall-wizards mailing list
firewall-wizards () honor icsalabs com
http://honor.icsalabs.com/mailman/listinfo/firewall-wizards

<I hope
you're not gonna say you have a web server on the *same* system as your
email gateway :-(  >. The web server legitimately uses the email gateway to
send emails out to the internet, but the web server has been exploited to
allow the intruder to send out emails which are tracked back to "coming from
the web server."

Oh NO!! The web server and email server are separate machines and different subnets. Lots of separation there, however, 
there were some strange entries in the root mailbox on the web server. Here:

Return-Path: <apache () fmsws fishburne org>
Received: from fmsws.fishburne.org (fmsws.fishburne.org [127.0.0.1])
       by fmsws.fishburne.org (8.12.5/8.12.5) with ESMTP id h4T6no4A001254;
       Thu, 29 May 2003 02:49:50 -0400
Received: (from apache@localhost)
       by fmsws.fishburne.org (8.12.5/8.12.5/Submit) id h4T6nn7Y001252;
       Thu, 29 May 2003 02:49:49 -0400
Date: Thu, 29 May 2003 02:49:49 -0400
Message-Id: <200305290649.h4T6nn7Y001252 () fmsws fishburne org>
To: none () fishburne org
From: none () fishburne org ()
Subject: Ignore
to: Spankyparade () o2 pl

*/BEGINABCDFORMMAILfishburne.org/cgi-bin/formmail.cgiTSTSendMailTSTENDABCD
/*
--h4T6nq4A001256.1054190992/fmsws.fishburne.org--

From root () fmsws fishburne org  Thu May 29 04:02:02 2003
Return-Path: <root () fmsws fishburne org>
Received: from fmsws.fishburne.org (fmsws.fishburne.org [127.0.0.1])
       by fmsws.fishburne.org (8.12.5/8.12.5) with ESMTP id h4T8224A001423
       for <root () fmsws fishburne org>; Thu, 29 May 2003 04:02:02 -0400


The highlit portion tells me that the attacker used a command in the body of an e-mail to send mail from the web server via sendmail. I also found that in the sendmail.cf , our mailserver was listed as the "smarthost". That got changed pretty quick. The formmail has been deleted as well. Things have gotten much quieter on the mail server since.

--
Robert E Martin
IT Manager
Fishburne Military School
rmartin () fishburne org
540.946.7726


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