Exploit:

  Systems Affected: Ultrix systems with X11 libs
  installed yet lacking a /dev/xcons.

  Problem: /usr/lib/X11/xconsole can be used to
  destructively overwrite any file on the system.
  To duplicate set the display to a working server,
  create a symbolic link from /tmp/Xconsole.log to
  the file to be overwritten, and run xconsole. The
  target file will be overwritten with a single line
  error message concerning a nonexistant /dev/xcons.

  Solution: The problem can be eliminated by creating
     are root read-writeable touchfile as /dev/xcons.