On Tuesday, an international team of researchers unveiled BadRAM, a proof-of-concept attack that completely undermines security assurances that chipmaker AMD makes to users of one of its most expensive and well-fortified microprocessor product lines. Starting with the AMD Epyc 7003 processor, a feature known as SEV-SNP—short for Secure Encrypted Virtualization and Secure Nested Paging—has provided the cryptographic means for certifying that a VM hasn’t been compromised by any sort of backdoor installed by someone with access to the physical machine running it.
I’m not really surprised, common wisdom is if someone malicious has hardware access to a machine it’s compromised. And if you don’t trust your hosting provider to not tamper with your machine, you should really find a new provider (or buy your own server).
The “trusted execution environment” thing was an attempt to make the system less vulnerable to exploitation through physical access. As we can see, it works about as well as expected.