source: http://www.securityfocus.com/bid/6331/info Mac OS X is the BSD-derived operating system distributed and maintained by Apple Sofware. It has been reported that a denial of service exists in OS X. When a user creates a directory, descends it, creates another directory of the same name, then attempts to move the directory up one level in the hierarchy, the system reacts unpredictably. It has been reported that this can cause a crash of the system. mkdir ~/mydir; cd ~/mydir; mkdir mydir; mv mydir ..