Security Enhancement of Out-of-band Remote Management in IaaS Clouds

Abstract

In Infrastructure-as-a-Service (IaaS) clouds, the users manage the systems in the provided virtual machines (VMs) called user VMs through remote management software such as Virtual Network Computing (VNC). For dependability, they often perform out-of-band remote management via the management VM. Even in the case of system failures inside their VMs, the users could directly access their systems. However, the management VM is not always trustworthy in IaaS. Once outside or inside attackers intrude into the management VM, they could easily eavesdrop on all the inputs and outputs in remote management. To solve this security issue, this paper proposes FBCrypt for preventing information leakage via the management VM in out-of-band remote management. FBCrypt encrypts the inputs and outputs between a VNC client and a user VM using the virtual machine monitor (VMM). Sensitive information is protected against the management VM between them. The VMM intercepts the reads of virtual devices by a user VM and decrypts the inputs, whereas it intercepts the updates of a framebuffer by a user VM and encrypts the pixel data. We have implemented FBCrypt for para-virtualized and fully-virtualized guest operating systems in Xen and TightVNC. Then we confirmed that any keystrokes or pixel data did not leak.