Monitoring terminal lines - is it a problem?

[Bill Nickless]

Is it possible, with AT&T System V UNIX, for a system administrator, (or
more importantly, a hacker who has gained root privelege) to monitor 
character I/O on a tty line?  What about a rlogin session?

We do not want this capability available on our system, however, we would like
to know if and how it is implementable so that we can know what to look for
and to protect against.  Also, reasons why it may or may not be difficult 
would be interesting as well.

The situation is this: some of the faculty would like access through the
department's UNIX system to the campus administrative system.  The campus
administrators have a concern that a line might be monitored from within
the UNIX system such that sensitive information such as grades and other
personal information could be compromised.  

This monitoring capabiliity is present on the administrative, non-UNIX 
system, and is relatively easy to implement on that system (or so I've 
been told).  To my knowledge it has not been done on our system.

Is this a valid concern for a UNIX system?  Or is it more likely someone
will do a hardware intercept on a RS-232 line?

Please send mail, I will post a summary or respond to mail.
-- 
Bill Nickless                    Andrews University Computer Science Department
...!sharkey!aucis!bnick or bnick at aucis.UUCP                  Unix Support Group

              "Help!  I'm locked up in this .signature factory!"