Index: /trunk/doc/manual/en_US/user_Security.xml
===================================================================
--- /trunk/doc/manual/en_US/user_Security.xml	(revision 39762)
+++ /trunk/doc/manual/en_US/user_Security.xml	(revision 39763)
@@ -50,4 +50,9 @@
                 as a regular user. We strongly discourage anyone from executing
                 VirtualBox with system privileges.
+              </para>
+              <para>
+                Choose restrictive permissions when creating configuration files,
+                for instance when creating /etc/default/virtualbox, see
+                <xref linkend="linux_install_opts"/>. Mode 0600 would be preferred.
               </para>
             </glossdef>