Design And Implementation Of Xen Virtualization Environment Vulnerability Detection Method

As virtualization technology becomes widely adopted, it is used by more and more corporations and organizations. Xen, an open source virtualization software, plays an important role in both commercial activities and scientific research. However, Xen vulnerability is a critical threat to applications running on Xen hypervisor. Although there is no doubt that establishing a solid security mechanism is important, detecting and repairing vulnerabilities on Xen system before any incident occurs is more essential.Now there are many vulnerability detection tools for example Nessus and Metasploit. Many vulnerability detection tools are able to detect vulnerabilities on operating systems, web applications and various software. Unfortunately, very few detection mechanisms and tools are available for detecting Xen vulnerability.This paper aims to study Xen vulnerability and vulnerability detection methods including studying principle of triggering Xen vulnerability and designing methods to detect Xen vulnerability. This paper regards Xen hypercall-related vulnerability as the main object of study, analyzes and designs detection methods for three Xen hypercall vulnerabilities including’ XENMEM_exchange’ local privilege escalation vulnerability, ’physdev_get_free_pirq’ denial of service vulnerability and ’Grant Table’ local denial of service vulnerability. Firstly, the paper presents the in-depth study of Xen-related knowledge and technology, including architecture, hypercall, memory management, security performance of Xen. Besides, this paper analyzes security problems and existing vulnerabilities of Xen as well as methods and tools to detect Xen vulnerabilities. According to the above conclusions on Xen, this work identifies specific type of Xen vulnerability to be detected, then, proposes a Xen vulnerability detection method which combines penetration testing with Xen vulnerability detection, that is, designing an attack program for each vulnerability and determining whether there is vulnerability by result of the program. The paper implements the above three vulnerability detection methods by means of loadable kernel module. Finally, this paper builds a vulnerable version of Xen and tests every above method. Experiment shows that specific vulnerability can be effectively detected by the method.This paper studies three vulnerabilities that exist in process of invoking hypercall and we can trigger these vulnerabilities by constructing specific ways of invoking hypercall. There are many similar vulnerabilities exist and the same attack mode can also be applied in these similar hypercall vulnerabilities becoming detection method for more Xen hypercall vulnerabilities.