Proceedings in pdf format. - Sociotechnical Systems Engineering ...

increasingly important, as electronic transaction systemshave become widespread in use.All services may be needed at every stage, given therequirements of various services and applications,ranging from e-commerce applications that use protocolsat high layers to connection privacy and link availabilityat low layer protocols.DEFENCE-IN-DEPTH STRATEGYLast concepts of security approaches in securitydomain are based on so called defence-in-depth strategywhich states that all information technology assets withina protected network need to have the necessary amountof security protection to guard against direct attacks atwhatever level the asset resides within the network(Security Certified Program 2006).The main idea is to protect information at all stages itis being used and retransmitted in terms of provision ofone or more of the security services.Defence-in-depth strategy centres on maintainingappropriate security measures and procedures (providingdescribed security services) at five different levels withinenvironment (Ashley 2006):• Perimeter (entry points to the network);• Network (enterprise data transmission network);• Host (workstation or server);• Application (any application running on host);• Data (data storage protection).This strategy allows addressing the majority of threatsto security due to solutions used at essential informationprocessing stages.From the other side, defence-in-depth strategy andsecure network architecture oriented approaches are likepatches – they try to protect network (resources andinformation stored) from some defined threats (mostlypredefined) using specific products or techniques. Themajority of networks historically have heterogeneousenvironments, thus introducing great problem to solutionmanagement and consolidation. Separated, often isolatedproducts addressing only specific threats cannot provideintegrated security, allowing unaddressed threats orthreats to newly discovered (and thus unaddressed)vulnerabilities still are possible.Evaluation of effectiveness of security measures beingused in most cases is hard to accomplish. This is becausethere are no mechanisms to control interaction andeffectiveness of security techniques used and nomechanism is used to address new threats andvulnerabilities except published software patches andfixes.In most cases even these manufacturer providedcritical updates could not be easily applied in productionenvironment because the effect of applying such updatesin most cases is not predictable.As environment changes, some new threats appearand some old disappear. Risk analysis should beperiodically performed and security systems should bechanged reflecting environment changes for securitysystems to be able to provide the same level of protectionand be able to correctly act in new conditions (forinstance, changes in security procedure or firewallconfiguration reflecting new IT technology introduced inorganization).Therefore, by the nature, defence-in-depth strategybased on secure network architecture fails to guaranteeintegrated security, because, first, for problem solving ituses different solutions often with poor consolidation.Second, system that realizes protection from specificthreats is as secure, as complete threat inventory wasperformed during design phase (which almost always issubjective). In any case, there still is possibility that allpossible threats and potential vulnerabilities will never bediscovered.Thus, approach to network security based on “securearchitecture” with defence-in-depth strategy could notprovide necessary level of protection. Such approachtypes does not examine correct solution interaction on allOSI layers and periodic vulnerabilities in protocols andprimitives used.NEED FOR STANDARDIEZED SECURITYMODELTechnologies such as firewalls, intrusion detectionsystems, and antivirus software have become extremelypopular in the security domain. They however only solvevery specific problems and in no means provide securityassurance. Instead, their importance has beenoveremphasised, or rather: other aspects of systemsecurity have been neglected or have receivedinsufficient attention. Security features are oftenimplemented because of a direct threat. Systems aredesigned with functionality and efficiency in mind butoften fail to make a thorough investigation of the securityrequirements of the application as well as the underlyingsystem. This inevitably leads to patches or securitysoftware or hardware being used at later stages of thedevelopment cycle, often after vulnerability has beenexploited.This lack of coordination between securityrequirements and security measures might lie with thefact that there are currently no clearly defined guidelinesas to the requirements of the individual parts of a system.Many organisations such as financial institutions haveclearly defined business requirements. However, thesebusiness requirements have little relation to thespecification and the implementation of the system. Thisclearly indicates that some process is required toformalise the implementation of a secure system andachieve a state of security assurance.Annual Proceedings of Vidzeme University College “ICTE in Regional Development”, 2006128