RE: email address "spoofed"

[JULIO CALDERON <JULIO.CALDERON () ttisg com>]

This is an NDR attack, your system is probably being overwhelmed with
receipts of undeliverable messages and if you look into your outbox you
probably also have messages with Null senders.

If this is happening then you should establish an antispamm solution, A
gateway that will check every message and it's content then block anything
that was not originated by any of your domain users, etc.

How is this done? Very easily! 

But how are these viruses/worms exploiting this SMTP hole? Not sure, would
have to do a search for the code to find out.

Best Regards
Julio Calderon




-----Original Message-----
From: Adrian Hall [mailto:ad3y () hotmail com] 
Sent: Wednesday, March 10, 2004 1:52 PM
To: security-basics
Subject: Re: email address "spoofed"

You can spoof a domain name but the IP Address will give away the sending
server.
> From this you can use reverse DNS to identify either the owner of the domain
or their ISP.
Once you have these details then you can report the incident to either the
administrator for that domain or the ISP's abuse email address.
Hopefully then the admin or ISP will contact the abuser and put a stop to
the problem - which seems mostly to be the result of virus infections on
home PC's of late.

These are about the only steps you can take to tackle the real issue but if
the problem continues and uses the same IP Address (or limited range of
addresses) each time then you should be able to block incoming traffic from
that (or those) addresses that is destined for Port 25 on your mail server.

Regards,

Ade.

----- Original Message ----- 
From: "Luis E. Alvarado Day" <lalvarado () frro utn edu ar>
To: <hometeam () goeaston net>; "security-basics"
<security-basics () securityfocus com>
Sent: Tuesday, March 09, 2004 3:10 AM
Subject: Re: email address "spoofed"


> There´s nothing to do for that problem. There are lot´s of servers over
the
> internet that allow any person to send emails with any domain name they
> desire. For example i can send emails from the
> presidente () presidencia gov ar.
> Try using certificated emails, that could help your customers/users to
know
> if the mails they receive a really sent by you.
>
> ----- Original Message -----
> From: "Tim Laureska" <hometeam () goeaston net>
> To: "security-basics" <security-basics () securityfocus com>
> Sent: Friday, March 05, 2004 3:59 AM
> Subject: email address "spoofed"
>
>
> > I'm not sure if "spoofing" is the correct term but here is what has
> > happened:
> >
> > Someone is sending out email messages (with virus laden attachments)
> > using our domain name  ... they are addressed as coming from
> > support () ourdomainname com (ourdomainame would be our actual domain name)
> > which is an email address that we never set up.
> >
> > My question is how is this done and is there anything we can do to
> > prevent this in the future?  The message header looks like this:
> >
> > Received: from your-xhtr8hvc4p [68.55.1.207] by ourdomainname.com
> >   (SMTPD32-8.05) id A3C8DF0118; Fri, 05 Mar 2004 04:09:28 -0500
> > Date: Fri, 05 Mar 2004 04:07:07 -0500
> > To: info () ourdomainname com
> > Subject: E-mail account security warning.
> > From: support () ourdomainname com
> > Message-ID: <oruybbfoofisdsegtve () ourdomainname com>
> > MIME-Version: 1.0
> > Content-Type: multipart/mixed;
> >         boundary="--------hggfurquvkrsejwodibt"
> > X-RCPT-TO: <info () ourdomainname com>
> > Status: U
> > X-UIDL: 355598192
> >
> >
> > Tim
>
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---------------------------------------------------------------------------
Ethical Hacking at the InfoSec Institute. Mention this ad and get $545 off
any course! All of our class sizes are guaranteed to be 10 students or less
to facilitate one-on-one interaction with one of our expert instructors.
Attend a course taught by an expert instructor with years of in-the-field
pen testing experience in our state of the art hacking lab. Master the skills
of an Ethical Hacker to better assess the security of your organization.
Visit us at:
http://www.infosecinstitute.com/courses/ethical_hacking_training.html
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