Mastering Linux Security and Hardening - Second Edition

The sudo timer

By default, the sudo timer is set for five minutes. This means that once a user performs one sudo command and enters a password, he or she can perform another sudo command within five minutes without having to enter the password again. Although this is obviously handy, it can also be problematic if users were to walk away from their desks with a command terminal still open.

If the five-minute timer hasn't yet expired, someone else could come along and perform some root-level task. If your security needs require it, you can easily disable this timer by adding a line to the Defaults section of the sudoers file. This way, users will have to enter their passwords every time they run a sudo command. You can make this a global setting ...