You’ve not really given us much to go on but the question is why do they need it?
If they need it to manage the server then giving them access to dom0 from a domu makes no difference than giving access to the world by giving them the root password. Dom0 should be treated like a domu, it is in itself a VM only is has more functionaility and can obviously destroy the server in the wrong hands. This is of course assuming you have no lock down on dom0 with iptables etc.
In answer to the question about threat to domu, probably not much if it is just SSH access.
I think you need to give more info on how your current system is configured and what the reasons are for the requirement you have specified.
Personally I wouldn’t want anyone having access to dom0 unless it was for management purposes and then they would be accountable for anything going wrong.
Ian
From: xen-users-bounces@xxxxxxxxxxxxx [mailto:xen-users-bounces@xxxxxxxxxxxxx] On Behalf Of Omkar Kulkarni
Sent: 12 May 2012 21:26
To: xen-users@xxxxxxxxxxxxx
Subject: [Xen-users] Need help
Is it possible to get dom0 access from domU? And if I have dom0 access, what are the threats to domU? Is it possible to simulate an attack on dom0 or domU? I need a urgent help, As my academic work I am working on it.