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Disable Guest battery state api

Posted: 30. Mar 2020, 17:26
by 0bsidian
I use VirtualBox on a Win10 laptop. I have created a Win7 VM.
The VM shows the battery level status of the Host. This data is sent to websites (browserleaks com/javascript#battery)
For privacy concerns I don't want this to happen. I know of some workaround options like using security addons, or Firefox, but I'm particularly looking for a way to disable it in general from VirtualBox.

I have tested disabling the battery devices form the vm's device manager, but it's not the solution.

Re: Disable Guest battery state api

Posted: 31. Mar 2020, 00:57
by scottgus1
Searching the PDF of the manual, there's one spot mentioning putting host battery level into the guest:
the manual, 'features overview', wrote:Full ACPI support. The Advanced Configuration and Power Interface (ACPI) is fully
supported by Oracle VM VirtualBox. This enables easy cloning of disk images from real
machines or third-party virtual machines into Oracle VM VirtualBox. With its unique
ACPI power status support, Oracle VM VirtualBox can even report to ACPI-aware guest
OSes the power status of the host. For mobile systems running on battery, the guest
can thus enable energy saving and notify the user of the remaining power, for example
in full screen modes.
There is no other place in the manual that shows how to keep such info from getting into a guest, unless you're running a Solaris host.

So you would need to block ACPI in the guest OS. This might also stop the guest from responding to the 'ACPIpowerbutton' commands in Virtualbox too.

Re: Disable Guest battery state api

Posted: 31. Mar 2020, 10:51
by 0bsidian
Thank you @scottgus1. From the few results I found regarding this issue, I read blocking ACPI can break a lot of things, but since this seems to be the only possible option, I'll test and report back.