Final answer:
A PB security class override in a permission-based security system is usually applied at the user or group level by system administrators to temporarily change a user's access rights.
Step-by-step explanation:
In the context of a user's record on a computer system, a PB security class override typically refers to an action taken within a Permission-Based (PB) security system. These systems are commonly used in software applications to manage user access to different parts of the system. Applying a security class override often occurs at the user or group level, depending on the permissions granted by the system administrators. This allows for the adjustment of access rights for individual users or groups of users beyond what is set by the default security class.
For example, in a database application, a user might normally have read-only access to sensitive data. However, under certain circumstances, it might be necessary to grant that user the ability to edit or add to the data. In such a case, an authorized administrator would apply a security class override at the user level to temporarily elevate the user's permissions.
It's important to note that managing these overrides requires a solid understanding of both the security requirements of the system and the principles of least privilege, where users are given the minimum level of access necessary to perform their tasks to help prevent unauthorized access or data breaches.