Virtual Machine Security Challenges

1.2 Virtual Machine and Its Security Challenges

A virtual machine image is a single file which contains a virtual disk that has a bootable operating system installed on it. Virtual machines are becoming more common with the evolution of virtualization technology. Virtual machines are often created to perform certain tasks that are different than tasks performed in a host environment.

Virtual machines are implemented by software emulation methods or hardware virtualization techniques. Depending on their use and level of correspondence to any physical computer, virtual machines can be divided into two categories:

1.2.1 System Virtual Machines

A system platform that supports the sharing of the host computer 's physical resources between multiple

1.4 Challenges in virtualization

Virtualization technologies offer new economic and technical possibilities. However, the addition of a new layer of software introduces new security concerns. Garfinkel and Rosenblum give in [14] a list of challenges raised by virtualization that are discussed hereafter.

1.4.1 Scaling

Virtualization enables quick and easy creation of new virtual machines. Therefore, security policies of a network (setup, updates...) have to be flexible enough to handle a fast increase in the number of machines.

1.4.2 Transience

With virtualization, machines are often added to or removed from a network. This can hinder the attempts to stabilize it. For example, if a network gets infected by a worm, it will be harder to find precisely which machines were infected and clean them up when these machines exist only during brief periods of time on the network. Similarly, infected machines or still vulnerable ones can reappear after the infection was thought to be wiped

2.1 Mirage

Mirage [7] is an image management system for the cloud environment. The Mirage provides security to the VM images in four ways.

2.1.1 Access Control

Any user who wants to modify or publish VM Images needs proper permission.

2.1.2 Filters

Remove Filter and Hide Filter, Remove filter excludes any sensitive file from the Image and Hide Filter hide the private information or replaces it in safer version.

2.1.3 Auditing

In auditing all operations performed on images are reviewed from a tracking file. If there is any suspicious operation or user is introduced, it will take action against him

2.1.4 Maintenance Services

In [15] a novel tool named Nüwa developed to enable efficient patching of offline VM images. Nüwa uses safety analysis and script rewriting techniques to convert patches, or more specifically the installation scripts contained in patches, which were originally developed for online updating, into a form that can be applied to VM images offline. Figure 2. Structure of Mirage