GoKawiilA host connects to your network. It looks like part of your fleet, but is it really? It runs your software, or at least enough of it to start serving traffic. It quacks like a duck. But what’s on the inside?
I’m surprised ChatGPT agreed to make that one.
But seriously. How do you know that your data isn’t sitting on a compromised stack? How do you know that you aren’t trying to schedule workloads on an attacker controlled machine? How do you know any of your security controls are actually in place on a host? And once an attacker has taken over a host, there are endless places to hide and persist through upgrades and reboots.
Most setups have a lot of faith in hosts once they have been provisioned. Hosts are placed in the trust boundary and then just remain there, regardless of whatever has happened in the mean time. If they even should have been there in the first place.
Enter the wonderful world of remote attestation which (mostly) solves this problem. Using a TPM, we can remotely, cryptographically prove a couple of things:
The host has the expected hardware
The host has the expected firmware
The host has the expected kernel and init image
The host has the expected root filesystem (depends on the setup)
The host passed arbitrary checks that we define
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