Eliminate Covert Channels

Covert channels in privileged applications should be sought out and eliminated. A covert channel is an unintended path through which information can be transmitted in ways not protected by mandatory access controls. For example, in a privileged multilabel client/server application, the server has a queue of service requests. If unprivileged clients can add and remove requests from the queue and the queue has a finite size, the information on the full or not-full state of the queue can be exploited as a covert channel.