| dc.description.abstract | Cloud computing has gained remarkable popularity in the recent years by a wide spectrum of consumers, ranging from small start-ups to governments. However, its benefits in terms of flexibility, scalability, and low upfront investments, are shadowed by security challenges which inhibit its adoption. In particular, these highly flexible but complex cloud computing environments are prone to misconfigurations leading to security incidents, eg, erroneous exposure of services due to faulty network security configurations. In this thesis we present a novel approach in the security assessment of multi-tier architectures deployed on infrastructure clouds such as Amazon EC2. In order to perform this assessment for the currently deployed configuration, we automated the process of extracting the configuration using the Amazon API and translating it into a generic data model for later analysis. In the assessment we focused on the reachability and vulnerability of services in the virtual infrastructure, and presented a way for the visualization andautomated analysis based on reachability and attack graphs. We proposed a query and policy language for the analysis which can be used to obtain insights into the configuration and to specify desired and undesired configurations. We have implemented the security assessment in a prototype and evaluated it for practical andtheoretical scenarios. Furthermore, a framework is presented which allows the evaluation of configuration changes in the agile and dynamic cloud environments with regard to properties like vulnerabilities or expected availability. In case of a vulnerability perspective, this evaluation can be used to monitor the securitylevels of the configuration over its lifetime and to indicate degradations. | nb_NO |
