Discretionary Access Control (DAC) means that the owner of an object can manage permissions for the object at his own discretion. In effect, owner of an object can decide who to grant permissions to access and use the object to without the decision being questioned by the OS. An example of this is permissions associated with UNIX files which the owner of the file is allowed to modify with no restrictions. It is DAC that is to blame for gaining-the-privileges portion of the attack mechanisms. Once the attacker gets hold of ``flow of execution'' of the attacked program it may manipulate any of the objects owned by the uid running the process [30,23,22]. Individual attempts have been made3.2 at configuring the DAC in a fine-grained enough manner to minimize the described effect but all of them yielded complex and bulky solutions that were impossible to maintain and control.