# An Access Control Model for Preventing Virtual Machine Hopping Attack
## 1 Introduction  
Cloud computing is an Internet-based, emerging network computing model. It is another new computing concept after parallel computing, grid computing, and utility computing [1]. It is regarded as another revolution in the computer field. With the gradual development and advantages of cloud computing, the core technologies and applications of cloud computing have been highly valued by governments, companies, and scientific research institutions. Many IT companies such as Google [2], Amazon [3], Azure and Alibaba have taken cloud computing as an important direction for future technological innovation and invested heavily in research and development. Many countries even regard cloud computing as an important opportunity to develop and upgrade the information industry and promote the development of the information society. In the investigation report of the RightScale 2018 status, 96% of IT professionals surveyed said that their company was adopting cloud computing services, and 92% said they used public clouds. As companies move more applications to the cloud, the cloud computing market is increasingly booming. According to research firm Gartner, the public cloud market value will reach 186.4 billion US dollars in 2018, an increase of 21.4% over last year. While IT leaders decided to adopt cloud computing because of the benefits they bring, they still face a very important cloud computing challenge, one of which is security. The virtual machine (VM) hopping attack [4; 5] studied in this paper mainly involves the security between different virtual machines on the same host and the security between the virtual machine and the host. In a cloud platform, multiple virtual machines are distributed together on the same physical machine. If a virtual machine is compromised or an illegal intruder obtains the highest authority of a virtual machine by some means, there is a security risk that an illegal user uses the virtual machine as a springboard to attack other virtual machines and even attack the virtual machine manager to illegally obtain data files on the virtual machine. There are various vulnerabilities in different virtualization platforms. A Xen official announced a major security vulnerability, codenamed \"Dome Breaking\" (XSA-148/CVE-2015-7835). It shows that there is exploitable vulnerability in virtual machines running in the Para-Virtualized (PV) mode of the Xen platform, which is prone to virtual machinehopping attacks and virtual machine escaping attacks. [PERSON] of Crowdstrike found a security vulnerability related to the virtual floppy controller in the open source computer emulator QEMU, codenamed \"VENOM\" (CVE-2015-3456). It existed in many computer virtualization platforms (notably Xen, KVM, VirtualBox, and the native QEMU client). This vulnerability could allow an attacker to get rid of the guest identity restrictions from an infected virtual machine and likely to gain code execution rights from the host. In addition, an attacker can use it to access the host system and all virtual machines running on the host, and can elevate access permissions so that attackers can access the host's local network and neighboring systems. Another vulnerability (CVE-2018-10853) indicated that KVM 4.10 and later versions in the Linux kernel have security flaws in implementation due to the failure to detect the CPL (the privilege level of the currently executing task or program). An attacker could exploit this vulnerability to elevate privileges and cause virtual machine hopping attacks. Since the virtual machine hopping attack is a security risk of the virtualization layer, the security risks in the virtualization layer may cause the security system of the entire cloud computing platform to collapse. Therefore, if a virtual machine hopping attack occurs in the cloud platform, huge damage is brought to the entire cloud platform.