See also the official CERT Advisory [1] on vulnerabilities in the ID4 Alien/OS, warning of potential denial of service attacks by inferior life forms and recommending various workarounds in the event that planetary takeover is necessary (yes, it's a joke, but having been published within hours of the first screening of the movie this may well have been the fastest CERT vulnerability response in history)

[1] http://users.rcn.com/alderete/humor/comp/id4.html