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Message #66094
[Bug 1681465] Re: VNC connection to VMs is unprotected
** Changed in: nova
Status: New => Opinion
** Changed in: nova
Importance: Undecided => Wishlist
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https://bugs.launchpad.net/bugs/1681465
Title:
VNC connection to VMs is unprotected
Status in OpenStack Compute (nova):
Opinion
Status in OpenStack Security Advisory:
Won't Fix
Bug description:
Description:
============
OpenStack Nova does not provide any protection of VNC servers running
on compute nodes by default. Any client that has access to management
network can connect to the consoles of VMs running on compute node and
obtains full access to VMs via the console (e.g. by rebooting VMs to
single-user mode).
Steps to reproduce
==================
- Configuration: the management interface of the compute node has a public IP address and is not protected by firewalls
- Create a VM on the compute node
- Use a VNC client to connect directly to the IP of the compute node via port 590x from anywhere.
Expected result
===============
Connections refused. Only VNC connections from master node should be accepted. Other should connect using proxy on master node which does also authorization
Actual result
=============
Connection accepted. Anyone can use VNC client to connect directly to the console of VMs running on the compute node without any authentication/authorization
Discussion
===========
To be fair, most of examples in the OpenStack documentation have
management networks private, so the network configuration in the
examples are safe. However, OpenStack documentation only emphasizes
the separation of management network from other networks (VM, data)
and does not explicitly require (in a visible way) that the management
networks must be protected (private networks, firewalls). The
management network may be separated to another (public) network
segment and the system is still vulnerable to the VNC attack.
Therefore, the VNC connection to compute nodes should be protected
(password, iptables) by default, or the documentation should give
explicit warning that the management network must be private or
protected by firewalls.
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