Get the Most from Least Privilege

In spy novels, secret agents often operate on a need-to-know basis, in which each agent is told only what he or she must know to fulfill his or her individual mission. Restricting the amount of information granted to each agent helps protect the overall operation. The IT equivalent of this model is the concept of least privilege, in which each user account is granted only the privileges required to fulfill that user's role and responsibilities. Least privilege helps limit the damage that can result from the spread of malware, user mistakes, or abuse by disgruntled employees or malicious intruders. To put the concept into practice, you need to determine which privileges various roles require, create groups to manage those roles, then apply the concept to groups, services—and administrators.

Use Auditing
The first step in implementing least privilege is identifying each user's roles and responsibilities so that you can then determine the minimum set of user rights and permissions necessary. When you then begin to set up formal role-based authority on a system, you'll likely encounter the situation in which a user account obviously lacks an essential right or permission, but because of uninformative error messages and poor documentation, you can't figure out exactly what that right or permission is. In such situations, the Windows Security log is invaluable. . . .