Secure Encrypted Virtualization (SEV) was touted as one of the killer features of AMD EPYC and Ryzen Pro series processors. It involves encryption of parts of the memory of the host machine which house virtual machines (or guests), with encryption keys stored on the processor, so the host has no scope of infiltrating or reading the contents of the guest's memory. This was designed to build trust in cloud-computing and shared hosting industries, so web-present small businesses with sensitive data could have some peace of mind and wouldn't have to spend big on dedicated hosting. A Germany-based IT security research team from Fraunhofer AISEC, thinks otherwise.

Using a technique called "SEVered," the researchers were able to use rogue host-level administrator, or malware within a hypervisor, to bypass SEV and copy decrypted information from the guest machine's memory. The exploit involves alteration of the guest machine's physical memory mappings using standard page tables, so SEV can't properly isolate and encrypt parts of the guest in the physical memory. The exploit is so brazen, that you could pull plaintext information out of compromised guests. The researchers published a paper on SEVered, along with technical details of the exploit.