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Survivable Systems Analysis MethodSurvivability ConceptsThe success of virtually all organizations in business, government, and defense is dependent on the availability and correct functioning of large-scale networked information systems of astonishing complexity. Because of the severe consequences of failure, organizations are focusing on system survivability as a key risk management step.Survivability is the capability of a system to fulfill its mission in a timely manner, even in the presence of attacks or failures. Survivability goes beyond security and fault tolerance to focus on delivery of essential services, even when systems are penetrated or experience failures, and rapid recovery of full services when conditions improve. Unlike traditional security measures that require central control and administration, survivability addresses highly distributed, unbounded network environments that lack central control and unified security policies.
The Three Rs: Resistance, Recognition, and RecoveryThe focus of survivability is on delivery of essential services and preservation of essential assets. Essential services and assets are those system capabilities that are critical to fulfilling mission objectives. Survivability depends on three key capabilities: resistance, recognition, and recovery. Resistance is the capability of a system to repel attacks. Recognition is the capability to detect attacks as they occur and to evaluate the extent of damage and compromise. Recovery, a hallmark of survivability, is the capability to maintain essential services and assets during attack, limit the extent of damage, and restore full services following attack.
Survivable Systems Analysis: Addressing Architecture SoftspotsThe Survivable Systems Analysis (SSA) method (formerly the Survivable Network Analysis method) was developed by the SEI CERT® Coordination Center. SSA is a practical engineering process that permits systematic assessment of the survivability properties of proposed systems, existing systems, and modifications to existing systems. The analysis is carried out at the architecture level as a cooperative project by an SEI team working with your team of system architects, developers, and stakeholders. The method proceeds through a series of joint working sessions, culminating in a briefing on findings and recommendations.The SSA method provides a means for organizations to understand survivability in the context of their operating environments. What functions must survive? What intrusions could occur? How could intrusions affect survivability? What are the business risks? How could architecture modifications reduce the risks? Systematic consideration of these questions through SSA reveals the risks and leads to mitigation strategies. The SSA method is composed of four steps, as follows:
SSA DeliverablesThe SSA method produces the following deliverable items for the selected system:
These deliverables are provided in a final report and briefing to your management team, and provide a basis for risk analysis, cost/benefit trade-off, and system improvement.
SSA BenefitsThe SSA process raises awareness of survivability exposures in the systems your organization and customers depend on. SSA helps avoid unpleasant surprises. It provides a management roadmap for addressing exposures before the fact rather than consequences after the fact. System survivability means mission survivability for most organizations. It is more effective to manage survivability risks up front than to manage damage control later.
For More InformationFor information on how the CERT/CC can provide an SSA for your organization, contactDr. Nancy Mead at 412 / 268-5756, Email: nrm@sei.cmu.edu
CERT Coordination Center
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Last updated November 12, 2002
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