source: https://www.securityfocus.com/bid/1005/info

A vulnerability exists in the manner in which RedHat Linux 6.0 protects the obtaining of a shell by booting single user mode. RedHat will prompt for the root password upon entering single user mode. Pressing ^C (causing a SIGINT to be sent) immediately results in a root shell being made available.

boot single user from lilo, and press ^C (control-C)