On Tue, Jul 16, 2013 at 10:22:30AM -0400, Matthew Miller wrote:
On Tue, Jul 16, 2013 at 10:58:52AM +0100, Richard W.M. Jones wrote:
> Cloud-init is reasonably careful about where it gets the data from.
> By default it looks first for a config drive (a specially formatted
> block device which has to be explicitly added to the VM), and then
> secondly for a webserver on a link-local IPv4 address (usually
> 169.254.169.254). Also, if configured, a specially formatted virtual
> floppy or virtual CD-ROM drive can be used. None of these can be used
> to remotely exploit a VM "connected to the public Internet [etc]."
The attack would be something else on the link-local network responding to
169.254.169.254. So it's not "the public internet" in general, but
connecting to an untrusted network.
I don't think I view this cloud-init scenario as a security issue really.
That cloud-init pulls config off the network is well defined & intended
behaviour. So I think this is mostly a case of educating users about the
requirements for deploying the cloud images, so that they're aware of the
implications of using them in a non-cloud environment. Probably something
to be written on the download page.
Daniel
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