Enable Authentication for Single-User Mode

Single-User mode is used for a system recovery. However, by default, no authentication is used if single-user mode is selected. This can be used to bypassing security on the server and gaining root access. To enable authentication for single-user mode, open the /etc/inittab, file:
# vi /etc/inittab

Add the following line to the file:
~~:S:wait:/sbin/sulogin

Save and close the file.


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