Hackers of India

Back to the Future: A Radical Insecure Design of KVM on ARM

 Baibhav Singh   Rahul Kashyap 

2018/08/08

In ARM there are certain instructions that generates exception. Such instructions are typically executed to request a service from software that runs at a higher privilege level. From the OS kernel (EL1), software can call the Hypervisor (EL2) with the HVC instruction.

The KVM Hypervisor is part of the Linux kernel and by default it is enabled on all supported ARM system. In ARM architecture KVM is implemented through split-mode virtualization and runs across different privileged CPU modes. This talk will discuss about the design and a security issue in a way Linux kernel initializes the KVM Hypervisor. An attacker having access to host EL1 can execute code in EL2. This security issue can be exploited by an attacker to install a Hypervisor root kit on ARM system.