Earlier quoted context omitted.
It is kind of a fundamental risk of IMDS, the guest vms often need some metadata about themselves, the host has it. A hardened, network gapped service running host side is acceptable, possibly the best solution. I think the issue is if your IMDS is fat and vulnerable, which this article kind of alludes to. There’s also the fact that azure’s implementation doesn’t require auth so it’s very vulnerable to SSRF
You could imagine hosting the metadata service somewhere else. After all there is nothing a node knows about a VM that the fabric doesn’t. And things like certificates comes from somewhere anyway, they are not on the node so that service is just cache.
Ah yes great point, awesome article by the way —- thought provoking, shocking, really crazy stuff. Hopefully some good comes of it, godspeed.