NT has undergone a maturing process, and part of that process has been the hard practical realities of intruders. Like any complex software system, NT Server and NT Workstation have a history of bugs that intruders have been able to exploit. While Microsoft has been able to fix most of the problems, there is never such a thing as a 100 percent assurance that security is totally airtight. It's therefore useful to have an understanding of the nature of these attacks in order to be prepared for any contingency. More important, knowledge of NT vulnerabilities, even if Microsoft has fixed them, helps increase awareness of how vital implementation details are in assuring security.