Researchers Defeat AMD's SEV Virtual Machine Encryption
May 28, 2018
German security researchers claim to have found a new practical attack against virtual machines (VMs) protected using AMD's Secure Encrypted Virtualization (SEV) technology that could allow attackers to recover plaintext memory data from guest VMs. AMD's Secure Encrypted Virtualization (SEV) technology, which comes with EPYC line of processors, is a hardware feature that encrypts the memory of each VM in a way that only the guest itself can access the data, protecting it from other VMs/containers and even from an untrusted hypervisor. Discovered by researchers from the Fraunhofer Institute for Applied and Integrated Security in Munich, the page-fault side channel attack, dubbed SEVered, takes advantage of lack in the integrity protection of the page-wise encryption of the main memory, allowing a malicious hypervisor to extract the full content of the main memory in plaintext from SEV-encrypted VMs. Here's the outline of the SEVered attack, as briefed in the paper :...
