When You use 'sudo' command it will ask for password in First time and will remember password for 15 minutes. It is a security hole for sensitive systems.
You can change sudo Password Remembering Time in Ubuntu .
Open a terminal and type
$ sudo visudo
In Ubuntu, visudo uses nano text editor, and what it does is edit the / etc / sudoers.tmp
Check for the line as shown below
Change it to
Defaults env_reset , timestamp_timeout = X
Where X is the time that we remember the sudo password, if we put 0 (zero) that we always get the request.
Finally to save the changes, press Ctrl + X and said yes.