How to disable CTRL-ALT-DEL from rebooting a Linux system

Hitting CTRL-ALT-DELETE on most Linux distributions will start the soft reboot process. Normally I like to disable this (at least on production systems) because someone might make a mistake and reboot the system. Also what I don’t like about this shortcut is that you don’t need to be logged in (no user/password needed - but only console access) to reboot the system.

The action taken for CTRL-ALT-DEL is defined in /etc/inittab and if we will look in that file we will see a line similar to the one from bellow (taken from a Debian system):

# What to do when CTRL-ALT-DEL is pressed.
ca:12345:ctrlaltdel:/sbin/shutdown -t1 -a -r now

On other Linux distributions this might look a little different… anyway we are looking for the line containing **ctrlaltdel **in /etc/inittab. Here is another example: on RedHat based systems this line will look like:

ca::ctrlaltdel:/sbin/shutdown -t3 -r now

If we want to disable this action we only have to change this line. We can delete it, comment it, or even replace it with something like:

ca:12345:ctrlaltdel:/bin/echo "CTRL-ALT-DEL is disabled"

After making any changes to the inittab file, you will have to tell init to reload it, in order to activate the changes. To do that, simply run as root:

init q