Re: Re: mail server vulnerability

[greimer () fccc edu]

> But I still would like how to block telnet access
> to port 25 on a linux machine (Centos 5.2).
     Email IS telnet to port 25, isn't it?

Yours,

(George) Kurt Reimer
Fox Chase Cancer Center


On Fri, 20 Feb 2009, Atilla Remote Support wrote:

> Hi Praveen.
>
> Can you tell me how to disable telnet login to the
> smtp port?
> I've got telnet daemon disabled on a server, but
> still I can telnet to port 25.
> However this does not mean that people can do
> email relaying because the MTA takes care of that.
> Also the banner name is changed so people can't
> see which mta and which version is running, it's
> stating a fake application and version number.
>
> But I still would like how to block telnet access
> to port 25 on a linux machine (Centos 5.2).
>
> Regards,
>
> Richard.
>
>
> ----- Original Message -----
> From: <praveen_recker () sify com>
> To: <security-basics () securityfocus com>
> Sent: Friday, February 20, 2009 4:37 PM
> Subject: Re: Re: mail server vulnerability
>
>
> > Hi Abhishek,
> >
> > You can try connecting to the SMTP server using
> > telnet,say
> > c:/>telnet smtp_ip 25
> > this should not be successful....so system
> > admins should block TELNET to SMTP servers. If
> > successful this gives u the banner. Based upon
> > version and vendor search for any exploits
> > available for free (refer milw0rm, metasploit
> > etc) if u have commercial tools(coreimpact,
> > saint etc) it's well and good.
> > If u are good at Perl develop ur own script and
> > start sending attacks by changing USER names,
> > DOMAIN names etc to overly long strings, format
> > specifiers etc.
> >
> > Best Regards,
> > Praveen Darshanam,
> > Security Researcher,
> > INDIA