AdminSysGNULinux

Source : https://www.linuxtechi.com/disable-reboot-using-ctrl-alt-del-keys/

In Linux , It’s a security concern for us to allow anyone to reboot the server using Ctrl-Alt-Del keys. It is always recommended in production boxes that one should disable reboot using Ctrl-Alt-Del keys.

In this article we will discuss how can we disable reboot via above keys in RHEL & CentOS

To prevent the init process from handling Ctrl-Alt-Del, edit the file /etc/inittab :

/etc/inittab

# Trap CTRL-ALT-DELETE
#ca::ctrlaltdel:/sbin/shutdown -t3 -r now

We can also modify the line to generate logs, if anybody try to reboot the server using the keys ,

/etc/inittab

# Trap CTRL-ALT-DELETE
ca::ctrlaltdel:/bin/logger -p authpriv.warning -t init "Console-invoked Ctrl-Alt-Del was ignored"

In RHEL 6.X / CentOS 6.X , reboot using the keys are handled by the file /etc/init/control-alt-delete.conf.

Step:1 Before making the changes, first take the backup using below command

cp -p /etc/init/control-alt-delete.conf{,.orig}

Step:2 Edit the file, replacing the exec /sbin/shutdown line with the following, which will simply generate a log entry each time Ctrl-Alt-Del is pressed:

/etc/init/control-alt-delete.conf

exec /usr/bin/logger -p authpriv.notice -t init "Ctrl-Alt-Del was pressed and ignored"

Run either of the beneath command from the console to disable reboot using ‘CTRL+ALT+DELETE’ keys in RHEL 7.x and CentOS 7.x

ln -sf /dev/null /etc/systemd/system/ctrl-alt-del.target

OR

systemctl mask ctrl-alt-del.target

reboot.target https://www.2daygeek.com/how-to-avoid-or-prevent-accidental-shutdown-or-reboot-on-linux/

# systemctl mask reboot.target
Created symlink /etc/systemd/system/reboot.target → /dev/null.

# systemctl mask poweroff.target
Created symlink /etc/systemd/system/poweroff.target → /dev/null.

# systemctl mask halt.target
Created symlink /etc/systemd/system/halt.target → /dev/null.