Context: Cloud computing is a prospering technology that most organizations are considering for adoption as a cost effective strategy for managing IT. However, organizations also still consider the technology to be associated with many business risks that are not yet resolved. Such issues include security, privacy as well as legal and regulatory risks. As an initiative to address such risks, organizations can develop and implement SLA to establish common expectations and goals between the cloud provider and customer. Organizations can base on the SLA to measure the achievement of the outsourced service. However, many SLAs tend to focus on cloud computing performance whilst neglecting information security issues. Objective: We identify threats and security attributes applicable in cloud computing. We also select a framework suitable for identifying information security metrics. Moreover, we identify SLA based information security metrics in the cloud in line with the COBIT framework. Methods: We conducted a systematic literature review (SLR) to identify studies focusing on information security threats in the cloud computing. We also used SLR to select frameworks available for identification of security metrics. We used Engineering Village and Scopus online citation databases as primary sources of data for SLR. Studies were selected based on the inclusion/exclusion criteria we defined. A suitable framework was selected based on defined framework selection criteria. Based on the selected framework and conceptual review of the COBIT framework we identified SLA based information security metrics in the cloud. Results: Based on the SLR we identified security threats and attributes in the cloud. The Goal Question Metric (GQM) framework was selected as a framework suitable for identification of security metrics. Following the GQM approach and the COBIT framework we identified ten areas that are essential and related with information security in the cloud computing. In addition, covering the ten essential areas we identified 41 SLA based information security metrics that are relevant for measuring and monitoring security performance of cloud computing services. Conclusions: Cloud computing faces similar threats as traditional computing. Depending on the service and deployment model adopted, addressing security risks in the cloud may become a more challenging and complex undertaking. This situation therefore appeals to the cloud providers the need to execute their key responsibilities of creating not only a cost effective but also a secure cloud computing service. In this study, we assist both cloud provider and customers on the security issues that are to be considered for inclusion in their SLA. We have identified 41 SLA based information security metrics to aid both cloud providers and customers obtain common security performance expectations and goals. We anticipate that adoption of these metrics can help cloud providers in enhancing security in the cloud environment. The metrics will also assist cloud customers in evaluating security performance of the cloud for improvements.

Em um mundo tecnológico e globalmente interconectado, em que indivíduos e organizações executam transações na web com frequência, a questão da segurança de software é imprescindível, ela é necessária em diversos nichos: segurança das redes de computadores, dos computadores e dos softwares. A implantação de um sistema de segurança que abrange todos os aspectos é extensa e complexa, ao mesmo tempo em que a exploração de vulnerabilidades e ataques é exponencialmente crescente. Por causa da natureza do software e de sua disponibilidade na web, a garantia de segurança nunca será total, porém é possível planejar, implementar, medir e avaliar o sistema de segurança e finalmente melhorá-la. Atualmente, o conhecimento específico em segurança é detalhado e fragmentado em seus diversos nichos, a visão entre os especialistas de segurança é sempre muito ligada ao ambiente interno da computação. A medição de atributos de segurança é um meio de conhecer e acompanhar o estado da segurança de um software. Esta pesquisa tem como objetivo apresentar uma abordagem top-down para medição da segurança de acesso de aplicações web. A partir de um conjunto de propriedades de segurança reconhecidas mundialmente, porém propriedades estas intangíveis, é proposta uma metodologia de medição e priorização de atributos de segurança para conhecer o nível de segurança de aplicações web e tomar as ações necessárias para sua melhoria. Define-se um modelo de referência para segurança de acesso e o método processo de análise hierárquica apoia a obtenção de atributos mensuráveis e visualização do estado da segurança de acesso de uma aplicação web. / In a technological world and globally interconnected, in which individuals and organizations perform transactions on the web often, the issue of software security is essential, it is needed in several niches: security of computer networks, computers and software. The implementation of a security system that covers all aspects is extensive and complex, while the exploitation of vulnerabilities and attacks are increasing exponentially. Because of the nature of software and its availability on the web, ensure security will never be complete, but it is possible to plan, implement, measure and evaluate the security system and ultimately improve it. Currently, the specific knowledge in security is detailed and fragmented into its various niches; the view among security experts is always connected to the internal environment of computing. The measurement of security attributes is a way to know and monitor the state of software security. This research aims to present a top-down approach for measuring the access security of web applications. From a set of security properties globally recognized, however these intangible properties, I propose a measurement methodology and prioritization of security attributes to meet the security level of web applications and take necessary actions for improvement. It is defined a reference model for access security and a method of analytic hierarchy process to support the achievement of measurable attributes and status of the access security of a web application.

Em um mundo tecnológico e globalmente interconectado, em que indivíduos e organizações executam transações na web com frequência, a questão da segurança de software é imprescindível, ela é necessária em diversos nichos: segurança das redes de computadores, dos computadores e dos softwares. A implantação de um sistema de segurança que abrange todos os aspectos é extensa e complexa, ao mesmo tempo em que a exploração de vulnerabilidades e ataques é exponencialmente crescente. Por causa da natureza do software e de sua disponibilidade na web, a garantia de segurança nunca será total, porém é possível planejar, implementar, medir e avaliar o sistema de segurança e finalmente melhorá-la. Atualmente, o conhecimento específico em segurança é detalhado e fragmentado em seus diversos nichos, a visão entre os especialistas de segurança é sempre muito ligada ao ambiente interno da computação. A medição de atributos de segurança é um meio de conhecer e acompanhar o estado da segurança de um software. Esta pesquisa tem como objetivo apresentar uma abordagem top-down para medição da segurança de acesso de aplicações web. A partir de um conjunto de propriedades de segurança reconhecidas mundialmente, porém propriedades estas intangíveis, é proposta uma metodologia de medição e priorização de atributos de segurança para conhecer o nível de segurança de aplicações web e tomar as ações necessárias para sua melhoria. Define-se um modelo de referência para segurança de acesso e o método processo de análise hierárquica apoia a obtenção de atributos mensuráveis e visualização do estado da segurança de acesso de uma aplicação web. / In a technological world and globally interconnected, in which individuals and organizations perform transactions on the web often, the issue of software security is essential, it is needed in several niches: security of computer networks, computers and software. The implementation of a security system that covers all aspects is extensive and complex, while the exploitation of vulnerabilities and attacks are increasing exponentially. Because of the nature of software and its availability on the web, ensure security will never be complete, but it is possible to plan, implement, measure and evaluate the security system and ultimately improve it. Currently, the specific knowledge in security is detailed and fragmented into its various niches; the view among security experts is always connected to the internal environment of computing. The measurement of security attributes is a way to know and monitor the state of software security. This research aims to present a top-down approach for measuring the access security of web applications. From a set of security properties globally recognized, however these intangible properties, I propose a measurement methodology and prioritization of security attributes to meet the security level of web applications and take necessary actions for improvement. It is defined a reference model for access security and a method of analytic hierarchy process to support the achievement of measurable attributes and status of the access security of a web application.

For several years a trend in agile software development methodologies that connect the development with operations is transforming business activities in the industry. This methodology, that breaks down the formerly separated silos of development and operations is commonly referred to as DevOps. From a security point of view, however, the DevOps methodology lacks a fundamental integration of security in any of its phases. As a result of that, the DevSecOps practice, that intertwines the disciplines of security, development and operations is more and more gaining popularity. The biggest challenge in this shift of practice is the flawless introduction of security methods into existing DevOps processes without disturbing the fast pace and responsiveness of those. Whereas the security integration and processes on how to make DevOps secure are discussed in various preceding studies, this research focuses on an investigation of criteria that can be used to measure application security in DevSecOps integration. Given the lack of a fundamental base of academic literature on the topic, a Multivocal Literature Review (MLR) was conducted. For the study, not only academic research but also gray literature such as blogs and articles from industry practitioners were investigated to extract meaningful review criteria. As applicable, high-level criteria, agreed-upon best-practices and descriptions of security controls were thereby examined and compiled out of the studied literature. The criteria resulting from the conducted MLR process were further analyzed with each criterion's coverage in existing security standards in mind. Additionally, an investigation of a criterion's connection to the fundamental principles of the DevOps methodology was performed. The resulting list of criteria as well as additional, partially classified sub-criteria are presented as the primary contribution of the thesis. Further, a discussion of the results and evaluation of the criteria for measurability and applicability with the help of an expert group from the cooperating company Veriscan Security AB was performed. Lastly, the conducted study highlights the current state of research on the topic, discusses the lack of knowledge for particular areas as well as serves as a foundation and suggestion for several fields of future research. The criteria could, for instance, enable future design science research on DevSecOps security measurement.

Users’ trust in online situations is influenced by various characteristics of human-computer interaction. Looking at the increasing scope of services online, it remains an up-to-date issue, expanding its meaning for both informational and transactional websites. In this work, the Scale for Online Users’ Trust (SCOUT) was developed to assess the trustworthiness of both types of websites. Based on the scale, the effects of user experience on users’ trust were examined in several studies. For informational websites, hedonic qualities appeared to be significant predictors of trustworthiness in addition to usability. The effects could be confirmed for transactional websites. Furthermore, perceptions of security aspects were investigated in a set of studies. The effects of customer ratings, fictitious graphical elements, web assurance seals and interactive security-related feedback on users’ trust were analyzed. Findings from all together 11 studies of this work allow for inferences for website design that could support academics and practitioners in designing for trustworthy web environments. / Nutzervertrauen in Websites ist sowohl auf informationalen als auch auf transaktionalen Websites nach wie vor ein entscheidender Faktor für erfolgreiche Online-Situationen. In dieser Arbeit wird die Entwicklung des Fragebogens SCOUT (Scale for Online Users’ Trust) beschrieben, mit dem die Vertrauenswürdigkeit von Websites beider Kategorien gleichermaßen erfasst werden kann. Darauf aufbauend wurde die Wirkung des Nutzererlebens auf Vertrauen in mehreren Studien untersucht. Für informationale Websites ergaben sich hedonische Merkmale und Usability als signifikante Prädiktoren von Vertrauenswürdigkeit. Diese Effekte konnten für transaktionale Websites bestätigt werden. Zusätzliche wurde geprüft, wie Kundenbewertungen, fiktive grafische Elemente, Gütesiegel und interaktive sicherheitsrelevante Rückmeldungen auf Nutzervertrauen wirken. Aus insgesamt elf Studien lassen sich Empfehlungen für eine vertrauensförderliche Website-Gestaltung ableiten.

Proactive approaches for preventing attacks through security measurements are crucial for preventing sophisticated attacks. However, proactive measures must employ qualitative security metrics and systemic measurement methodologies to assess security guarantees, as some metrics (e.g., entropy) used for evaluating security guarantees may not capture the capabilities of advanced attackers. Also, many proactive measures (e.g., data pointer protection or data flow integrity) suffer performance bottlenecks. This dissertation identifies and represents attack vectors as metrics using the knowledge from advanced exploits and demonstrates the effectiveness of the metrics by quantifying attack surface and enabling ways to tune performance vs. security of existing defenses by identifying and prioritizing key attack vectors for protection. We measure attack surface by quantifying the impact of fine-grained Address Space Layout Randomization (ASLR) on code reuse attacks under the Just-In-Time Return-Oriented Programming (JITROP) threat model. We conduct a comprehensive measurement study with five fine-grained ASLR tools, 20 applications including six browsers, one browser engine, and 25 dynamic libraries. Experiments show that attackers only need several seconds (1.5-3.5) to find various code reuse gadgets such as the Turing Complete gadget set. Experiments also suggest that some code pointer leaks allow attackers to find gadgets more quickly than others. Besides, the instruction-level single-round randomization can restrict Turing Complete operations by preventing up to 90% of gadgets. This dissertation also identifies and prioritizes critical data pointers for protection to enable the capability to tune between performance vs. security. We apply seven rule-based heuristics to prioritize externally manipulatable sensitive data objects/pointers. Our evaluations using 33 ground truths vulnerable data objects/pointers show the successful detection of 32 ground truths with a 42% performance overhead reduction compared to AddressSanitizer. Our results also suggest that sensitive data objects are as low as 3%, and on average, 82% of data objects do not need protection for real-world applications. / Doctor of Philosophy / Proactive approaches for preventing attacks through security measurements are crucial to prevent advanced attacks because reactive measures can become challenging, especially when attackers enter sophisticated attack phases. A key challenge for the proactive measures is the identification of representative metrics and measurement methodologies to assess security guarantees, as some metrics used for evaluating security guarantees may not capture the capabilities of advanced attackers. Also, many proactive measures suffer performance bottlenecks. This dissertation identifies and represents attack elements as metrics using the knowledge from advanced exploits and demonstrates the effectiveness of the metrics by quantifying attack surface and enabling the capability to tune performance vs. security of existing defenses by identifying and prioritizing key attack elements. We measure the attack surface of various software applications by quantifying the available attack elements of code reuse attacks in the presence of fine-grained Address Space Layout Randomization (ASLR), a defense in modern operating systems. ASLR makes code reuse attacks difficult by making the attack components unavailable. We perform a comprehensive measurement study with five fine-grained ASLR tools, real-world applications, and libraries under an influential code reuse attack model. Experiments show that attackers only need several seconds (1.5-3.5) to find various code reuse elements. Results also show the influence of one attack element over another and one defense strategy over another strategy. This dissertation also applies seven rule-based heuristics to prioritize externally manipulatable sensitive data objects/pointers – a type of attack element – to enable the capability to tune between performance vs. security. Our evaluations using 33 ground truths vulnerable data objects/pointers show the successful identification of 32 ground truths with a 42% performance overhead reduction compared to AddressSanitizer, a memory error detector. Our results also suggest that sensitive data objects are as low as 3% of all objects, and on average, 82% of objects do not need protection for real-world applications.