8.5 Do not use group, shared, or generic IDs, passwords, or other authentication methods as follows:

8.5 Do not use group, shared, or generic IDs, passwords, or other authentication methods as follows:
• Generic user IDs are disabled or removed.
• Shared user IDs do not exist for system administration and other critical functions.
• Shared and generic user IDs are not used to administer any system components.
8.5.a For a sample of system components, examine user ID lists to verify the following:
• Generic user IDs are disabled or removed.
• Shared user IDs for system administration activities and other critical functions do not exist.
• Shared and generic user IDs are not used to administer any system components.
8.5.b Examine authentication policies and procedures to verify that use of group and shared IDs and/or passwords or other authentication methods are explicitly prohibited.
8.5.c Interview system administrators to verify that group and shared IDs and/or passwords or other authentication methods are not distributed, even if requested.

If multiple users share the same authentication credentials (for example, user account and password), it becomes impossible to trace system access and activities to an individual. This in turn prevents an entity from assigning accountability for, or having effective logging of, an individual’s actions, since a given action could have been performed by anyone in the group that has knowledge of the authentication credentials.