A couple of German boffins have taken a good look at AMD's Secure Encrypted Virtualization (SEV), and don't like what they see.
As AMD's Brijesh Singh explained to the Linux driver project mailing list in April, SEV extends the AMD-V architecture when multiple VMs are running under a hypervisor: "SEV hardware tags all code and data with its VM ASID which indicates which VM the data originated from or is intended for. This tag is kept with the data at all times when inside the SOC, and prevents that data from being used by anyone other than the owner".
In this paper at Arxiv, Felicitas Hetzelt and Robert Buhren of the Technical University of Berlin identify shortcomings in the architecture, including possible encryption bypass, information leakage, and memory replay attacks.
[...] "The key idea of SEV is that guest memory is encrypted and the corresponding key is only accessed by the memory controller that handles the encryption and decryption transparently, thereby protecting against both a malicious hypervisor and physical attacks," they write. "This key will never be exposed to the hypervisor. Additionally AMD added a coprocessor to SEV-enabled CPUs ... This coprocessor handles key management and is responsible for the initial encryption of the guest."
[...] The good news is that all of the attacks need a malicious hypervisor – meaning customers can trust AMD SEV if they trust their cloud operator. Although they consider the design issues to be serious, the researchers note that "the technology is promising" if mitigations are possible.
(Score: 4, Funny) by dyingtolive on Friday December 09 2016, @02:18AM
Many boffins died to bring us this information.
Don't blame me, I voted for moose wang!
(Score: 0) by Anonymous Coward on Friday December 09 2016, @02:48AM
It would be a shame if it had a government sponsored backdoor in it, so 'all your keys belong to us', now wouldn't it?
That dystopian nightmare some of us feared is already here. The rest of you just won't realize it under long after it's been far too late to stop.
(Score: 0) by Anonymous Coward on Friday December 09 2016, @03:25AM
You're worried about government sponsored backdoors in hardware for public shared infrastructure services (clouds)?
There are so many points of entry available that don't involve in-flight attacks against running VMs.