Managing Systems and Workgroups: A Guide for HP-UX System Administrators

Administering a System: Managing System Security
Guidelines for Running a Secure System
Chapter 8782
Tracking Root
A useful method to keep track of system access and reduce security
breaches on standard and trusted servers is to physically secure the
system console and allow root to login only at the system console. Users
logging in through other ports must first log in as themselves, then
execute su to become root.
To limit root to logging in only through the system console, create the
/etc/securetty file with the single entry, console, as follows:
# echo console > /etc/securetty
This restriction applies to all login names that have user ID 0
(superuser). See login (1) for more details.