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RE: ESX Vmware Physically connected to different segments
From: "Loupe, Jeffrey J" <JLoupe () whitneybank com>
Date: Mon, 28 Jan 2008 15:35:29 -0600

You really can't compare ESX with any of the workstation products, or
vmware server, player, etc. Workstation was built with a certain level
of interaction with the underlying OS assumed and desired, such as USB
drive detection and the like. ESX was specifically designed to host
virtual machines. 

Shops that don't have the resources for a dedicated DMZ ESX host can,
with careful planning and administration, securely host virtual machines
on a DMZ and a trusted network. Shops that have the resources to have a
dedicated box should certainly consider that, since physically separate
is always more secure.

-J

-----Original Message-----
From: listbounce () securityfocus com [mailto:listbounce () securityfocus com]
On Behalf Of Kurt Buff
Sent: Monday, January 28, 2008 2:52 PM
To: David M. Zendzian
Cc: pen-test () securityfocus com
Subject: Re: ESX Vmware Physically connected to different segments

There are already exploits in the wild that detect if they are running
in a virtualized environment and abort themselves. I consider that the
canary in the coal mine.

While this:

http://securitydot.net/xpl/exploits/vulnerabilities/articles/1390/exploi
t.html

isn't about ESX, it's certainly on the right road, I believe.

Kurt

On Jan 28, 2008 12:32 PM, David M. Zendzian <dmz () dmzs com> wrote:
Yes it does make you think twice when considering such a design,
however
I am not familiar with exploits at a guest domain that would effect
the
host specifically. While yes in 'theory' there could be some kernel
hook
that could allow a guest to access the host server, and I hate to be
in
a situation when one arrives; however, the same argument also applies
to
shared virtual web hosts, but only the largest companies have
dedicated
hosts for every domain, there will always be sharing happening which
is
why virtual environments are growing in popularity.

Would it not be better to examine the hooks in systems that allow
communication / buffers / etc in virtual environments and help ensure
that they are done correctly? I know this is not really possible with
VMWare, but with Xen & other systems where the code is available the
issues can at least be investigated.

Now if someone has code (links/docs/etc) available the detail attacks
on
guests effecting hosts (DOS not included, exploits taking control of
services of a host from a guest, or accessing network or resources not
setup for that guest), then please post them to the list so we can
discuss the issues and how to address them.

These same questions might also be applied to VLANs or other types of
virtualization techniques that allow for greater use of the devices we
have available. While there are fun ways to attack network vlans to
access security domains outside of configured settings, it is the
disclosure of these techniques that allowed for providers to secure
the
tools to a point where I know of no business I've ever worked with
have
dedicated network devices for every network. While I have seen
different
equipment on "DMZ vs Internal" networks, most still use VLAN security
to
segment those as well (it's a $ thing & usually a complexity thing,
more
parts means more people to manage, understand, change w/ out breaking,
etc).

I believe there are ways of deploying virtual technology that may not
prevent the theoretical attack, at least provide protection against
the
common attacks and provide for a viable solution for the small
business'
I work with.

The only way to be secure is to unplug, the rest of us have to work
for
a living :)

David


Kurt Buff wrote:
Even if everything is configured properly, mixing security domains
in
a virtual hosting is a capital mistake.

That's because the underlying host is also vulnerable, and attacks
against a guest OS in an untrusted domain can be leveraged against
the
host, and from there *all* guest OSes are toast, or near to it.

Don't do it, ever.

Kurt

On Jan 28, 2008 5:08 AM, Loupe, Jeffrey J <JLoupe () whitneybank com>
wrote:

If everything is setup properly this configuration should be
secure. The
problem comes with misconfiguration. It's exceedingly easy for a
careless admin to connect a vNic to the wrong vSwitch and allow
traffic
meant for the DMZ onto the trusted network. In general we disallow
this
practice unless only one or two trusted admins have control of the
box.
Even then, we audit the configuration frequently.

-J

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________________________________________________________________

Confidentiality Notice:

This E-Mail transmission (and/or the documents accompanying it)
may contain information belonging to the sender which is 
confidential, privileged and/or exempt from disclosure under 
applicable law.  The information is intended only for the use
of the individual(s) or entity named above.   If you are not
the intended recipient, you are hereby  notified that any
disclosure, copying, distribution or the taking of any action
in reliance on the contents of this information is strictly 
prohibited.  If you have received this E-Mail transmission 
in error, please immediately notify us by return E-Mail or 
telephone to arrange for return of its contents including any
documents.

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