RE: VMWare poor guest isolation design

I'm trying to understand how the vm actually prevents the buffer overflow from injecting code that has direct hardware control? It seems that the code injected into memory should be truly "arbitrary code" based on the physical machine.

Are there any good papers that explain how the vm shields against buffer overflows?

KWK -----Original Message-----
From: Arthur Corliss [mailto:corliss@digitalmages.com] Sent: Friday, August 24, 2007 5:45 PM
To: Ken Kousky
Cc: bugtraq@securityfocus.com
Subject: RE: VMWare poor guest isolation design

On Fri, 24 Aug 2007, Ken Kousky wrote:

> This may be far off course but with all the discussions of VMWare as a
safe
> sandbox that has broad security value it seems we have to pay attention to
> the assumptions. IF the virtual machine is operating properly, it can
> provide a level of sandboxing and restrict session privileges for that
> instance of the machine. However, the most common exploit in software
> continues to be memory leakages or buffer overflows.
>
> It seems to me that the code that can be injected through the most common
> attack vector (buffer overflows) executes with full privileges of the real
> hosting machine, there would be little benefit to the virtualization. Am I
> missing something here?
>
> Is there a way that the arbitrary code injected through a buffer overflow
> can be constrained in the logical machine? It seems to me the VM can't
> provide this protection???

VMs can do just that, isolate the damage to the vm, with no impact to the host. This discussion never addressed that, though, it was focused on the premise that vms should be protected from the host operating system, which is exceedingly impractical. The host was never in danger from the techniques discussed here.

I think you may be referring to sandboxes like chroot & jails which are not quite as effective at isolating processes as the vm route. They have a hell of a lot less overhead, though.

 	--Arthur Corliss
 	  Live Free or Die