If you’re planning on taking the Security+ exam, you should have a good understanding of access control models such as role-BAC model access.
For example, can you answer this question?
Q. Your organization wants to reduce the administrative workload related to account management. Which of the following is the BEST choice?
A. Implement group-based privileges.
B. Implement user-based privileges.
C. Implement the Guest account and Guests group.
D. Implement periodic reviews of user access.
More, do you know why the correct answer is correct and the incorrect answers are incorrect? The answer and explanation is available at the end of this post.
Implementing Role-BAC Model
Administrators commonly grant access in the role-based access control (role-BAC) model using roles, and they often implement roles as groups. They assign rights and permissions (privileges) to groups and then add user accounts to the appropriate group. This type of group-based privileges, where access is based on roles or groups, simplifies user administration.
One implementation of the role-BAC model is the Microsoft built-in security groups, and specially created security groups that administrators create on workstations, servers, and within domains.
The Administrators group is an example of a built-in security group. For example, the Administrators group on a local computer includes all of the rights and permissions on that computer. If you want to grant Marge full and complete control to a computer, you could add Marge’s user account to the Administrators group on that computer. Once Marge is a member of the Administrators group, she has all the rights and permissions of the group.
Similarly, you can grant other users the ability to back up and restore data by adding their user accounts to the Backup Operators group. Although the built-in groups are very useful, they don’t meet all the requirements in most organizations. For example, if your organization wants to separate backup and restore responsibilities, you can create one group that can only back up data and another group that can only restore data.
In Windows domains, administrators often create groups that correspond to the departments of an organization. For example, imagine that Homer, Marge, and Bart work in the Sales department and need to access data stored in a shared folder named Sales on a network server. An administrator would simplify administration with the following steps, as shown in the following figure:
- Create a Sales group and add each of the user accounts to the Sales group.
- Add the Sales group to the Sales folder.
- Assign appropriate permissions to the Sales group for the Sales folder.
Establishing access with groups as roles
If the company adds new salespeople, the administrator creates accounts for them and places their account into the Sales group. These new salespeople now have access to everything assigned to this group. If any users change jobs within the company and leave the Sales department, the administrator removes them from the Sales group. This automatically prevents them from accessing any resources granted to the Sales group. This example shows how to use a group for the Sales department, but you can apply the same steps to any department or group of users.
Without groups, you would use user-assigned privileges. In other words, you would assign all the specific rights and permissions for every user individually. This may work for one or two users, but quickly becomes unmanageable with more users.
As an example, imagine that people within the Sales department need access to 10 different resources (such as files, folders, and printers) within a network. When the company hires a new salesperson, you’d need to assign permissions to these 10 different resources manually, requiring 10 different administrative tasks. If you assign the permissions to the Sales group, you only need to add the new user to one group and you’re done.
Groups provide another security benefit. Imagine that a user is promoted out of the Sales department and now works in Marketing. If you have a Marketing group, you can place this user account into the Marketing group and remove the account from the Sales group. Removing the user from the Sales group instantly removes all the rights and permissions from that group. However, if you’re not using groups and assign permissions to users directly, you probably won’t remember what resources were assigned to the user as a member of the Sales department. Instead, the user will continue to have access to this sales data, violating the principle of least privilege.
Chapter 8 of the CompTIA Security+: Get Certified Get Ahead: SY0-401 Study Guide presents information on reviews of user rights and permissions as part of an auditing process. A routine audit of user rights and permissions will detect when users have more rights and permissions than they need. However, using groups as part of a role-based access control model helps prevent the problem.
Remember this
Group-based privileges reduce the administrative workload of access management. Administrators put user accounts into groups, and assign privileges to the groups. Users within a group automatically inherit the privileges assigned to the group.
Q. Your organization wants to reduce the administrative workload related to account management. Which of the following is the BEST choice?
A. Implement group-based privileges.
B. Implement user-based privileges.
C. Implement the Guest account and Guests group.
D. Implement periodic reviews of user access.
Answer is A. Group-based privileges reduce the administrative workload related to account management because privileges are assigned to groups that share common responsibilities.
User-based privileges are extremely tedious and time consuming because privileges are assigned to all users individually.
Generic accounts such as Guest should not be used.
Implementing periodic user access reviews is a best practice to ensure accounts are managed properly, but they do not reduce the administrative workload.
