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Re: [Qemu-discuss] User Behavior Tracking defenses in VMs

From: bancfc
Subject: Re: [Qemu-discuss] User Behavior Tracking defenses in VMs
Date: Tue, 15 Mar 2016 19:22:43 +0100
User-agent: Roundcube Webmail/1.0.6

Interesting ideas Jakob. Where can I post this as a feature request so it gets more attention?

N.B. My second solution suggestion is not the way to go. High precision timers in virtualizers have bad security implications but there is no way around them. They enable side-channel attacks on crypto operations running on other VMs as well as aid in biometric fingerprinting. A multi hypervisor study on timer accuracy shows most have high accuracy by necessity. Increasing coarseness in the hypervisor's code can lead to guest slow downs or instability.[1] The amount of coarseness they can take varies by hypervisor. CPU load does NOT affect timer accuracy [in KVM] however IO does.

Paper: Achieving High Resolution Timer Events in Virtualized Environment

[1] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4503740/

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