Researcher Releases Hardened OS "Qubes"; Xen Hits 4.0

Trailrunner7 writes "Joanna Rutkowska, a security researcher known for her work on virtualization security and low-level rootkits, has released a new open-source operating system meant to provide isolation of the OS's components for better security. The OS, called Qubes, is based on Xen, X and Linux, and is in a basic, alpha stage right now. Qubes relies on virtualization to separate applications running on the OS and also places many of the system-level components in sandboxes to prevent them from affecting each other. 'Qubes lets the user define many security domains implemented as lightweight virtual machines (VMs), or 'AppVMs.' E.g. users can have 'personal,' 'work,' 'shopping,' 'bank,' and 'random' AppVMs and can use the applications from within those VMs just like if they were executing on the local machine, but at the same time they are well isolated from each other. Qubes supports secure copy-and-paste and file sharing between the AppVMs, of course.'" Xen's also just reached 4.0; some details below. Dominik Holling writes "With a small announcement on their mailing list, the open source community hypervisor Xen has reached the official release of version 4.0.0 today. The new features are: 'blktap2 (VHD support, snapshot discs, ...), Remus live checkpointing and fault tolerance, page sharing and page-to-disc for HVM guests, Transcendent memory (http://oss.oracle.com/projects/tmem/).' A complete list of all changes can be found on the Xen wiki and the source can be found on the official website and the Xen Mercurial repositories."

Comments

Re:Virtualization doesn't work vs. file macrovirus

[Jahava]

I think the idea is that you'd run different domains to protect different sets of files. You'd run your tax software in a "tax" domain, and if any PDF software got infected, it wouldn't be able to touch the "tax" domain information.

Versus locked-down operating systems, you have a valid point (and my personal issue with this approach). However, it's not without its advantages. In a standard Linux system, every userspace process has access to around 330 system calls. Each one of these is an interface into the kernel, and a bug in even one of them is enough to take over the kernel. Furthermore, any application that can load kernel modules can potentially dominate the kernel.

In the Qubes system, each domain is protected by a virtualization layer. It does have domainhypervisor interfaces (similar to system calls) to allow I/O, graphics, and the copy-paste subsystem to run, but there are a lot fewer of them. They are oriented around a finite functionality - the aforemented I/O, graphics, etc., while system calls must exist for all userspace functionality. Therefore, as userspace applications get more complex and system calls (per-domain) increase in number and complexity, the domainhypervisor interface will be more or less static. This hopefully leads to them being easier to secure and lock down.