No, a virtual machine is not as safe as a physical one!

This week, during the CanSecWest 2017 Conference in Vancouver, British Columbia, is held the PWN2OWN™ CONTEST organized by Zero-Day Initiative ( A team carried on an attack on Microsoft’s Edge browser allowing them to escape a VMware Workstation virtual machine in which it ran. This exploit fetched them 105 000$ of reward. On the same day, another team successfully exploited 3 vulnerabilities and succeed to perform a virtual machine escape.

I will state what is obvious to me since the rising of the hardware virtualization technologies: Virtual Machines aren’t as safe as Physical one. I feel stupid writing it as it is just a matter of fact but it seems it has not yet been accepted by a lot of system admins who are still in denial.

And VMware is not the only to blame, all the Virtualization solutions have already been breached (Xen, KVM,…) one way or another. And those ares just the known exploits. So, whoever you’re talking too, there is no way (s)he can pretend the risks are the same between a physical and a virtual machine.

Of course, there is economics upsides using virtualization and that’s why it is a matter of risk management. But when it comes to crown jewels, we might have to think twice or at least strongly insist on a physical segregation between more sensitive systems and internet facing one.

I don’t say we shouldn’t use virtual machine, I just say we must stop pretending they are as safe as physical one. It is just not true. Risk are different and we must take that into account. The wolfs can pass the fences…

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