The security access policy that contains fixed security attributes that are used by the system to determine a user’s access to a file or object is Mandatory Access Control (MAC). MAC is a type of access control model that assigns permissions to users and objects based on their security labels, which indicate their level of sensitivity or trustworthiness. MAC is enforced by the system or the network, rather than by the owner or the creator of the object, and it cannot be modified or overridden by the users. MAC can provide some benefits for security, such as enhancing the confidentiality and the integrity of the data, preventing unauthorized access or disclosure, and supporting the audit and compliance activities. MAC is commonly used in military or government environments, where the data is classified according to its level of sensitivity, such as top secret, secret, confidential, or unclassified. The users are granted security clearance based on their level of trustworthiness, such as their background, their role, or their need to know. The users can only access the objects that have the same or lower security classification than their security clearance, and the objects can only be accessed by the users that have the same or higher security clearance than their security classification. This is based on the concept of no read up and no write down, which requires that a user can only read data of lower or equal sensitivity level, and can only write data of higher or equal sensitivity level. MAC contains fixed security attributes that are used by the system to determine a user’s access to a file or object, by using the following methods:
Assigning security labels to the users and the objects, which consist of a security classification and a set of security categories. The security classification indicates the level of sensitivity of the data, such as top secret, secret, confidential, or unclassified. The security categories indicate the subject matter or the scope of the data, such as nuclear, military, or intelligence. The security labels are attached to the users and the objects as metadata or tags, and they cannot be changed or removed by the users.
Comparing the security labels of the users and the objects, using a reference monitor or an access control matrix. The reference monitor is a software component that intercepts and evaluates the requests for access to the objects, and grants or denies the access based on the security labels of the users and the objects. The access control matrix is a data structure that lists the users and the objects, and the permissions that each user has on each object, based on the security labels of the users and the objects.
