[Quick Tips] : Disable reboot using Ctrl-Alt-Del Keys

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 uisng Ctrl-Alt-Del keys.

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

For RHEL 5.X & CentOS 5.X

To prevent the init process from handling Ctrl-Alt-Del, edit the file  '/etc/inittab' comment the line which begins with 'ca::ctrlaltdel:'  as shown below :

[root@localhost ~]# cat /etc/inittab
# Trap CTRL-ALT-DELETE
#ca::ctrlaltdel:/sbin/shutdown -t3 -r now

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

[root@localhost ~]# cat /etc/inittab
# Trap CTRL-ALT-DELETE
ca::ctrlaltdel:/bin/logger -p authpriv.warning -t init "Console-invoked Ctrl-Alt-Del was ignored"

For RHEL6.X & CentOS 6.X

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

[root@localhost ~]# cp -v /etc/init/control-alt-delete.conf /etc/init/control-alt-delete.override

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:

[root@localhost ~]# cat /etc/init/control-alt-delete.conf
exec /usr/bin/logger -p authpriv.notice -t init "Ctrl-Alt-Del was pressed and ignored"