WELES: Policy-driven Runtime Integrity Enforcement of Virtual Machines
This addresses security concerns for cloud tenants deploying sensitive services, offering a novel approach to runtime integrity enforcement.
The paper tackles the problem of ensuring runtime integrity of virtual machines in the cloud against adversaries with administrative access, proposing WELES, a protocol that binds VM integrity to secure connections during login, with evaluation showing low performance overhead.
Trust is of paramount concern for tenants to deploy their security-sensitive services in the cloud. The integrity of VMs in which these services are deployed needs to be ensured even in the presence of powerful adversaries with administrative access to the cloud. Traditional approaches for solving this challenge leverage trusted computing techniques, e.g., vTPM, or hardware CPU extensions, e.g., AMD SEV. But, they are vulnerable to powerful adversaries, or they provide only load time (not runtime) integrity measurements of VMs. We propose WELES, a protocol allowing tenants to establish and maintain trust in VM runtime integrity of software and its configuration. WELES is transparent to the VM configuration and setup. It performs an implicit attestation of VMs during a secure login and binds the VM integrity state with the secure connection. Our prototype's evaluation shows that WELES is practical and incurs low performance overhead.