--- begin test.php ---
<?

$test = include("test.php");

?>
--- end test.php ---

This brought my whole server to it's knees. It basically ate all the resources it could find and filled up all the swap space until the kernel went "erk".

I haven't done much research but I'm aware that there are ways of detecting this kind of script.

Maybe this isn't really a bug, but it's something worth thinking about (or at least documenting).