Describe the SUID. Give an example of a command that typically has this permission set.

What will be an ideal response?

The SUID has no special function when set on a directory; however, if the SUID is set on a file and that file is executed, the person who executed the file temporarily becomes the owner of the file while it is executing. Many commands on a typical Linux system have this special permission set; the ping command that is used to test network connectivity is one such file. Because this file is owned by the root user, when a regular user executes the ping command, that user temporarily becomes the root user while the ping command is executing in memory. This ensures that any user can test network connectivity as the person who has all rights to do so on the system. Furthermore, the SUID can only be applied to binary compiled programs. The Linux kernel does not let you apply the SUID to a shell script because shell scripts are easy to edit and, thus, pose a security hazard to the system.