From elsewhere i have learned that there are a couple of ways to &quot;harden&quot; X.<p><a href="http:&#x2F;&#x2F;www.x.org&#x2F;wiki&#x2F;Development&#x2F;Documentation&#x2F;Security&#x2F;" rel="nofollow">http:&#x2F;&#x2F;www.x.org&#x2F;wiki&#x2F;Development&#x2F;Documentation&#x2F;Security&#x2F;</a> is one.<p>Another is to run each program inside their own &quot;server&quot;, via xnest, xephyr or similar.