The Time of Day
The Time of Day
Copyright(c) Management Analytics, 1995 - All Rights Reserved
Copyright(c), 1990, 1995 Dr. Frederick B. Cohen - All Rights Reserved
Problem:
Many operations depend on the time of day. For example, partial
backups are based on modification times, external systems may be polled
at certain times of day, maintenance tasks may be time dependent, etc.
A common protection technique is to add a time-lock to user login so
that they can only login from a particular terminal at a particular
time. By changing the time of day, all of these time dependent
functions can be made to happen at the wrong time. This can also
produce very subtle problems, for example, a remote system being polled
at the wrong time may prevent proper sending and receiving of mail.
Prevention:
Normally, the clock can only be changed by the superuser, so
good general protection practices will prevent almost all such problems.
Detection:
The `date' command will show the wrong time.
Cure:
The superuser can set the date and time with the `date' command.