A Framework and Calculation Engine for Modeling and Predicting the Cyber Security of Enterprise Architectures

University dissertation from Stockholm : KTH Royal Institute of Technology

Abstract: Information Technology (IT) is a cornerstone of our modern society and essential for governments' management of public services, economic growth and national security. Consequently, it is of importance that IT systems are kept in a dependable and secure state. Unfortunately, as modern IT systems typically are composed of numerous interconnected components, including personnel and processes that use or support it (often referred to as an enterprise architecture), this is not a simple endeavor. To make matters worse, there are malicious actors who seek to exploit vulnerabilities in the enterprise architecture to conduct unauthorized activity within it. Various models have been proposed by academia and industry to identify and mitigate vulnerabilities in enterprise architectures, however, so far none has provided a sufficiently comprehensive scope.The contribution of this thesis is a modeling framework and calculation engine that can be used as support by enterprise decision makers in regard to cyber security matters, e.g., chief information security officers. In summary, the contribution can be used to model and analyze the vulnerability of enterprise architectures, and provide mitigation suggestions based on the resulting estimates. The contribution has been tested in real-world cases and has been validated on both a component level and system level; the results of these studies show that it is adequate in terms of supporting enterprise decision making.This thesis is a composite thesis of eight papers. Paper 1 describes a method and dataset that can be used to validate the contribution described in this thesis and models similar to it. Paper 2 presents what statistical distributions that are best fit for modeling the time required to compromise computer systems. Paper 3 describes estimates on the effort required to discover novel web application vulnerabilities. Paper 4 describes estimates on the possibility of circumventing web application firewalls. Paper 5 describes a study of the time required by an attacker to obtain critical vulnerabilities and exploits for compiled software. Paper 6 presents the effectiveness of seven commonly used automated network vulnerability scanners. Paper 7 describes the ability of the signature-based intrusion detection system Snort at detecting attacks that are more novel, or older than its rule set. Finally, paper 8 describes a tool that can be used to estimate the vulnerability of enterprise architectures; this tool is founded upon the results presented in papers 1-7.