alt Hacker News> The direct corollary is that any successful compromise of the host can give an attacker access to the complete memory of every VM running on that node. Keeping the host secure is therefore critical.
> In that context, hosting a web service that is directly reachable from any guest VM and running it on the secure host side created a significantly larger attack surface than I expected.
That is quite scary
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This is well documented: https://learn.microsoft.com/en-us/azure/virtual-machines/ins...
Why would an Azure customer need to query this service at all? I was not aware this service even exists- because I never needed anything like it. AFAI can tell, this service tells services running on the VM what SKU the VM is. But how is this useful to the service? Any Azure users could tell how they use IMDS? Thanks!
Scary is the understatement of the day. I can't imagine the environment where someone think that architecture is a good idea.
Instead of zero trust, it is 110% trust.
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Like, what did the OP expect?
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