Changing the sudo timeout in Ubuntu

By default, Ubuntu remembers the sudo login for 15 minutes - this means you won't be prompted for your password for performing sudo operations for 15 minutes following a successful sudo login. This could be risky and can be changed so that the sudo password will be prompted for on every sudo login irrespective of the duration/timeout -

• Open terminal and type "sudo visudo"
• Locate the "Defaults ...." line as shown in the image below
• Add this to the end of the line - ",timestamp_timeout=0"
• Setting the timeout to 0 will prompt for the sudo password on every login. Alternatively this timeout can also be set to a number - e.g. setting it to 5 will remember the sudo password for 5 minutes.
• Save the file and exit

Further reference

• https://help.ubuntu.com/community/RootSudoTimeout