Aleksandar Milenkoski

Aleksandar Milenkoski, Samuel Kounev, Alberto Avritzer et al.

Modern intrusion detection systems (IDSes) for virtualized environments are deployed in the virtualization layer with components inside the virtual machine monitor (VMM) and the trusted host virtual machine (VM). Such IDSes can monitor at the same time the network and host activities of all guest VMs running on top of a VMM being isolated from malicious users of these VMs. We refer to IDSes for virtualized environments as VMM-based IDSes. In this work, we analyze state-of-the-art intrusion detection techniques applied in virtualized environments and architectures of VMM-based IDSes. Further, we identify challenges that apply specifically to benchmarking VMM-based IDSes focussing on workloads and metrics. For example, we discuss the challenge of defining representative baseline benign workload profiles as well as the challenge of defining malicious workloads containing attacks targeted at the VMM. We also discuss the impact of on-demand resource provisioning features of virtualized environments (e.g., CPU and memory hotplugging, memory ballooning) on IDS benchmarking measures such as capacity and attack detection accuracy. Finally, we outline future research directions in the area of benchmarking VMM-based IDSes and of intrusion detection in virtualized environments in general.

Aleksandar Milenkoski, Marco Vieira, Bryan D. Payne et al.

Modern virtualized service infrastructures expose attack vectors that enable attacks of high severity, such as attacks targeting hypervisors. A malicious user of a guest VM (virtual machine) may execute an attack against the underlying hypervisor via hypercalls, which are software traps from a kernel of a fully or partially paravirtualized guest VM to the hypervisor. The exploitation of a vulnerability of a hypercall handler may have severe consequences such as altering hypervisor's memory, which may result in the execution of malicious code with hypervisor privilege. Despite the importance of vulnerabilities of hypercall handlers, there is not much publicly available information on them. This significantly hinders advances towards securing hypercall interfaces. In this work, we provide in-depth technical information on publicly disclosed vulnerabilities of hypercall handlers. Our vulnerability analysis is based on reverse engineering the released patches fixing the considered vulnerabilities. For each analyzed vulnerability, we provide background information essential for understanding the vulnerability, and information on the vulnerable hypercall handler and the error causing the vulnerability. We also show how the vulnerability can be triggered and discuss the state of the targeted hypervisor after the vulnerability has been triggered.