Logical Specification and Analysis of Fault Tolerant Systems through Partial Model Checking

This paper presents a framework for a logical characterisation of fault tolerance and its formal analysis based on partial model checking techniques. The framework requires a fault tolerant system to be modelled using a formal calculus, here the CCS process algebra. To this aim we propose a uniform modelling scheme in which to specify a formal model of the system, its failing behaviour and possibly its fault-recovering procedures. Once a formal model is provided into our scheme, fault tolerance - with respect to a given property - can be formalized as an equational µ-calculus formula. This formula expresses in a logic formalism, all the fault scenarios satisfying that fault tolerance property. Such a characterisation understands the analysis of fault tolerance as a form of analysis of open systems and thank to partial model checking strategies, it can be made independent on any particular fault assumption. Moreover this logical characterisation makes possible the fault-tolerance verification problem be expressed as a general µ-calculus validation problem, for solving which many theorem proof techniques and tools are available. We present several analysis methods showing the flexibility of our approach

A model checking approach for verifying COWS specifications

We introduce a logical verification framework for checking functional properties of service-oriented applications formally specified using the service specification language COWS. The properties are described by means of SocL, a logic specifically designed to capture peculiar aspects of services. Service behaviours are abstracted in terms of Doubly Labelled Transition Systems, which are used as the interpretation domain for SocL formulae. We also illustrate the SocL model checker at work on a bank service scenario specified in COWS

Security Analysis of Parlay/OSA Framework

This paper analyzes the security of the Trust and Security Management (TSM) protocol, an authentication protocol which is part of the Parlay/OSA Application Program Interfaces (APIs). Architectures based on Parlay/OSA APIs allow third party service providers to develop new services that can access, in a controlled and secure way, to those network capabilities offered by the network operator. Role of the TSM protocol, run by network gateways, is to authenticate the client applications trying to access and use the network capabilities features offered. For this reason potential security flaws in its authentication strategy can bring to unauthorized use of network with evident damages to the operator and to the quality of the services. This paper shows how a rigorous formal analysis of TSM underlines serious weaknesses in the model describing its authentication procedure. This usually means that also the original system (i.e., the TSM protocol itself) hides the same flaws. The paper relates about the design activity of the formal model, the tool-aided verification performed and the security flaws discovered. This will allow us to discuss about how the security of the TSM protocol can be generally improve

A Logical Verification Methodology for Service-Oriented Computing

We introduce a logical verification methodology for checking behavioural properties of service-oriented computing systems. Service properties are described by means of SocL, a branching-time temporal logic that we have specifically designed to express in an effective way distinctive aspects of services, such as, e.g., acceptance of a request, provision of a response, and correlation among service requests and responses. Our approach allows service properties to be expressed in such a way that they can be independent of service domains and specifications. We show an instantiation of our general methodology that uses the formal language COWS to conveniently specify services and the expressly developed software tool CMC to assist the user in the task of verifying SocL formulae over service specifications. We demonstrate feasibility and effectiveness of our methodology by means of the specification and the analysis of a case study in the automotive domain

A Formal Security Analysis of an OSA/Parlay Authentication Interface

Abstract. We report on an experience in analyzing the security of the Trust and Security Management (TSM) protocol, an authentication procedure within the OSA/Parlay Application Program Interfaces (APIs) of the Open Service Access and Parlay Group. The experience has been conducted jointly by research institutes experienced in security and industry experts in telecommunication networking. OSA/Parlay APIs are designed to enable the creation of telecommunication applications outside the traditional network space and business model. Network operators consider the OSA/Parlay a promising architecture to stimulate the development of web service applications by third party providers, which may not necessarily be experts in telecommunication and security. The TSM protocol is executed by the gateways to OSA/Parlay networks; its role is to authenticate client applications trying to access the interfaces of some object representing an offered network capability. For this reason, potential security flaws in the TSM authentication strategy can cause the unauthorized use of the network, with evident damages to the operator and the quality of services. We report a rigorous formal analysis of the TSM specification, which is originally given in UML. Furthermore, we illustrate our design choices to obtain the formal model, describe the tool-aided verification and finally expose the security flaws discovered