Adding a user (useradd) via PHP - Ubuntu

I am trying to add a user to the server in a PHP script, however it's not working.

Here is my code:

$user = $_GET['user'];

system("sudo useradd -m -p 4dk/kBWvKaP5开发者_如何学JAVA2/POJYOZGLam8qZnCkQtdw== $user; echo $user");

Yes, I know how dangerous this is.

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You can set the setuid bit on the script file and chown it to root so it runs as root, e.g. chmod u+s file.php.