Re: Multiple Content (not working?)

["F.M. Taylor" <root () uranium indstate edu>]

Another thing that should be considered.  <voice of experience> Even when
FlexResp is working properly against an SMTP server all it does is drop
the connection at which time the MTA on their end simply tries again,
eating up your CPU and bandwidth.  You are only delaying the inevitable.  
</voe>

On Wed, 15 May 2002, Matt Kettler wrote:

> Hmm, as a bit of a side note, this sounds more like a job better fixed by 
> configuring your mailserver's access rules or using procmail than using snort.
>
> Also of note, Flexresp is *NOT* a sure thing and you should NEVER count on 
> it as a primary line of preventing a known attack. EVER. No, really, if 
> you're relying on flexresp to stop traffic you don't want you're going to 
> have it fail sooner or later. It's more of a last-ditch effort to stop an 
> attack that you did not know was possible on your network. It only really 
> has a chance of working due to network latencies, and a deliberate attacker 
> can fire off a second packet right behind the offending one to advance the 
> sequence number and likely do so before snort can respond.
>
> At any rate, given normal SMTP transactions the from and to lines are not 
> likely to be in the same TCP segment, since the server has to reply after 
> the "MAIL FROM" command and the "RCPT TO" command. Hence your pass rule 
> will not likely ever trigger in reality, unless the person delivering mail 
> to your server is not SMTP compliant and is just firing off commands 
> without waiting for acknowledgement from the server.
>
>
>
> At 05:26 AM 5/15/2002 -0300, you wrote:
> > Hello,
> >
> > I'm with some problems here while trying to configure
> > multiple content options to a rule.
> >
> > I need to block a unique e-mail address to send messages
> > to all my users, but this messages can be posted to me.
> >
> > well... I've tried two rules:
> > pass tcp $SMTPX any -> $MYSMTP 25
> > (content:"that () email com";nocase;content:"my () email com";n
> > ocase;)
> > alert tcp $SMTPX any -> $MYSMTP 25
> > (content:"that () email com";nocase;resp:rst_all;)
> >
> > May anyone help me to this work? plz!
> > I've lost some nights trying to figure out what's wrong.
> >
> > Thanks in advance.
> >
> >
> > Best Regards
> > __________________
> > Carlos Kumbak
> > ckumbak () bol com br
> >
> >
> > __________________________________________________________________________
> > Quer ter seu pr?prio endere?o na Internet?
> > Garanta j? o seu e ainda ganhe cinco e-mails personalizados.
> > Dom?niosBOL - http://dominios.bol.com.br
> >
> >
> >
> > _______________________________________________________________
> >
> > Have big pipes? SourceForge.net is looking for download mirrors. We supply
> > the hardware. You get the recognition. Email Us: bandwidth () sourceforge net
> > _______________________________________________
> > Snort-users mailing list
> > Snort-users () lists sourceforge net
> > Go to this URL to change user options or unsubscribe:
> > https://lists.sourceforge.net/lists/listinfo/snort-users
> > Snort-users list archive:
> > http://www.geocrawler.com/redir-sf.php3?list
>
>
> _______________________________________________________________
>
> Have big pipes? SourceForge.net is looking for download mirrors. We supply
> the hardware. You get the recognition. Email Us: bandwidth () sourceforge net
> _______________________________________________
> Snort-users mailing list
> Snort-users () lists sourceforge net
> Go to this URL to change user options or unsubscribe:
> https://lists.sourceforge.net/lists/listinfo/snort-users
> Snort-users list archive:
> http://www.geocrawler.com/redir-sf.php3?list


-- 
Mike Taylor
Coordinator of Systems Administration and Network Security
Indiana State University.               Rankin Hall Rm 053
210 N 7th St.                           Terre Haute, IN.
SANS GSEC  http://www.sans.org/


_______________________________________________________________

Have big pipes? SourceForge.net is looking for download mirrors. We supply
the hardware. You get the recognition. Email Us: bandwidth () sourceforge net
_______________________________________________
Snort-users mailing list
Snort-users () lists sourceforge net
Go to this URL to change user options or unsubscribe:
https://lists.sourceforge.net/lists/listinfo/snort-users
Snort-users list archive:
http://www.geocrawler.com/redir-sf.php3?list=snort-users