Viruses remain a significant threat to modern networked computer systems. Despite the best efforts of those who develop anti-virus systems, new viruses and new types of virus that are not dealt with by existing protection schemes appear regularly. In addition, the rate at which a virus can spread has risen dramatically with the increase in connectivity. Defenses against infections by known viruses rely at present on immunization yet, for a variety of reasons, immunization is often only effective on a subset of the nodes in a network and many nodes remain unprotected. Little is known about either the way in which a viral infection proceeds in general or the way that immunization affects the infection process. We present the results of a simulation study of the way in which virus infections propagate through certain types of network and of the effect that partial immunization has on the infection. The key result is that relatively low levels of immunization can slow an infection significantly.

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On computer viral infection and the effect of immunization

Survivability architectures enhance the survivability of critical information systems by providing a mechanism that allows the detection and treatment of various types of faults. In this paper, we discuss four of the issues that arise in the development of such architectures and summarize approaches that we are developing for their solution.

Survivability architectures: issues and approaches

We address the dependence of critical infrastructures-including electric power, telecommunications, finance and transportation-on vulnerable information systems. Our approach is based on the notion of control systems. We envision hierarchical, adaptive, multiple model, discrete state distributed control systems to monitor infrastructure information systems and respond to disruptions (e.g., security attacks) by changing operating modes and design configurations to minimize loss of utility. To explore and evaluate our approach, we have developed a toolkit for building distributed dynamic models of infrastructure information systems. We used this toolkit to build a model of a simple subset of the United States payment system and a control system for this model information system.

Information survivability control systems

The goal of a management system in a distributed computing environment is to provide a centralized and coordinated view of an otherwise distributed and heterogeneous collection of hardware and software resources. Management systems monitor, analyse and control network resources, system resources, and distributed application programs. Many organizations currently depend on mission-critical distributed applications, a trend that will increase as software engineering tools emerge that make it easier to construct distributed applications. We believe that manageability must be built in to distributed applications from the beginning rather than added in an ad hoc fashion after they have been developed. Just as designing software for usability, testability and maintenance are being addressed in the development process, so must designing for manageability. Application manageability is a research issue of particular interest to us. The work described in this paper focuses on instrumenting processes to allow them to respond to management requests, generate management reports, and maintain information required by the management system. We present an instrumentation architecture to support this, a prototype implementation which includes a class library of standard instrumentation, and a methodology for instrumentation.

/pdf/making-distributed-applications-manageable-through-2h3heh0izn.pdf

Making distributed applications manageable through instrumentation

A distributed computing system consists of heterogeneous computing devices, communication networks, operating system services, and applications As organisations move toward distributed computing environments, there will be a corresponding growth in distributed applications central to the enterprise The design, development, and management of distributed applications presents many difficult challenges As these systems grow to hundreds or even thousands of devices and similar or greater magnitude of software components, it will become increasingly difficult to manage them without appropriate support tools and frameworks Further, the design and deployment of additional applications and services will be, at best, ad hoc without modelling tools and timely data on which to base design and configuration decisions This paper presents a framework for management of distributed applications and systems The framework is based on a set of common management services that support management activities The services include monitoring, control, configuration, and data repository services A prototype system built on the framework is described that implements and integrates management applications providing visualisation, fault location, performance monitoring and modelling, and configuration management The prototype also demonstrates how various management services can be implemented

A. El Rayess

Papers

Services supporting management of distributed applications and systems