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4.4. Administrative Controls
When administering a home machine, the user must perform some tasks as the root user or by acquiring effective root privileges via a setuid program, such as
su. A setuid program is one that operates with the user ID (UID) of the program's owner rather than the user operating the program. Such programs are denoted by a lower case
sin the owner section of a long format listing, as in the following example:
-rwsr-xr-x 1 root root 47324 May 1 08:09 /bin/su
For the system administrators of an organization, however, choices must be made as to how much administrative access users within the organization should have to their machine. Through a PAM module called
pam_console.so, some activities normally reserved only for the root user, such as rebooting and mounting removable media are allowed for the first user that logs in at the physical console (see the chapter titled Pluggable Authentication Modules (PAM) in the Reference Guide for more about the
pam_console.somodule.) However, other important system administration tasks such as altering network settings, configuring a new mouse, or mounting network devices are not possible without administrative priveleges. As a result, system administrators must decide how much access the users on their network should receive.
4.4.1. Allowing Root Access
If the users within an organization are a trusted, computer-savvy group, then allowing them root access may not be an issue. Allowing root access by users means that minor activities, like adding devices or configuring network interfaces, can be handled by the individual users, leaving system administrators free to deal with network security and other important issues.
On the other hand, giving root access to individual users can lead to the following issues:
- Machine Misconfiguration — Users with root access can misconfigure their machines and require assistance or worse, open up security holes without knowing it.
- Running Insecure Services — Users with root access may run insecure servers on their machine, such as FTP or Telnet, potentially putting usernames and passwords at risk as they pass over the network in the clear.
- Running Email Attachments As Root — Although rare, email viruses that affect Linux do exist. The only time they are a threat, however, is when they are run by the root user.