Biblio

Organizations rely on security experts to improve the security of their systems. These professionals use background knowledge and experience to align known threats and vulnerabilities before selecting mitigation options. The substantial depth of expertise in any one area (e.g., databases, networks, operating systems) precludes the possibility that an expert would have complete knowledge about all threats and vulnerabilities. To begin addressing this problem of distributed knowledge, we investigate the challenge of developing a security requirements rule base that mimics human expert reasoning to enable new decision-support systems. In this paper, we show how to collect relevant information from cyber security experts to enable the generation of: (1) interval type-2 fuzzy sets that capture intra- and inter-expert uncertainty around vulnerability levels; and (2) fuzzy logic rules underpinning the decision-making process within the requirements analysis. The proposed method relies on comparative ratings of security requirements in the context of concrete vignettes, providing a novel, interdisciplinary approach to knowledge generation for fuzzy logic systems. The proposed approach is tested by evaluating 52 scenarios with 13 experts to compare their assessments to those of the fuzzy logic decision support system. The initial results show that the system provides reliable assessments to the security analysts, in particular, generating more conservative assessments in 19% of the test scenarios compared to the experts’ ratings. 

Recent data breaches in domains such as healthcare, where confidentiality of data is crucial, indicate that misuse cases often originate from user errors rather than vulnerabilities in the technical (software or hardware) architecture. Current requirements engineering (RE) approaches determine what access control mechanisms are needed to protect sensitive resources. However, current RE approaches inadequately characterize how a user is expected to interact with others in relation to the relevant resources. Consequently, a requirements analyst cannot readily identify the vulnerabilities based on user interactions. We adopt social norms as a natural, formal means of characterizing user interactions wherein potential misuses map to norm violations. Our research goal is to help analysts identify misuse cases by systematically generating potential temporal enactments that violate formally stated social norms. We propose Nane: a formal framework for identifying misuse cases from norm enactments. We represent misuse cases formally, and propose a semiautomated process for identifying misuse cases based on norm enactments. We show that our process is sound and complete with respect to the stated norms. We discuss the expressiveness of our representation, and demonstrate how Nane enables monitoring of misuse cases via temporal reasoning.