The security features of the operating system are useless if your
hardware and media are not protected.
You must physically protect the computer itself, the distribution media,
and any backup
media from unauthorized access:
Due to the design of the boot staging of most supported hardware platforms, any person with physical access to a system can easily circumvent any and all software security mechanisms. It is best to keep the system in a constantly supervised area. If supervision is not feasible, secure the area in which the computer is located by physically locking the system. Many systems provide key locks that electrically disconnect the keyboard; others provide CMOS password protection. The use of all these features may provide an adequate level of security.
If these measures are not possible, perform regular security checks as described in ``Database consistency checking: authck(ADM) and addxusers(ADM)'' and ``Unsupervised physical access to the computer''. Strict record-keeping and regular backups become more critical in this type of environment.