method for monitoring and controlling server applications through the use of low-cost, hidden channels

摘要

A covert channel is established between a network service and one or more service monitors in a service group. The covert channel minimizes overhead by providing an indication of the status of the service through use of operating system utilities rather than conventional remote procedure calls (RPCs) or posting methods. The covert channel relies on one or more communication files established and updated by the service and having attributes which are in proportion to the workload of the service. By monitoring these attributes, the service monitor is able to determine the status of the service, including its workload and availability, without incurring costly operational overhead.