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A comment on WSL2 corrupting Git repositories and shell history. Parent comment

Re:WSL2 corrupting Git repositories and shell history by proactivesvcs on Saturday January 02, 2021 @10:21AM (#25613364)
Enabling hardware virtualisation opens up a significant and deep attack surface. Considering the vanishingly small percentage of users which benefit from it, I hope it stays off by default.
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Re:WSL2 corrupting Git repositories and shell history by jrockway on Saturday January 02, 2021 @10:33AM (#25613450)
Windows is moving to a model where Windows itself is run as a virtualized OS. I believe this is enabled by default in new installs.

So having a Linux VM in Hyper-V isn't opening up much new attack surface.

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Re:WSL2 corrupting Git repositories and shell history by AshamedCaptain on Saturday January 02, 2021 @12:37PM (#25614502)
It's not enabled by default. Enabling Hyper-V still causes a battery/performance hit that is going to be hard to get rid of.
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Re:WSL2 corrupting Git repositories and shell history by smileybarry on Saturday January 02, 2021 @12:59PM (#25614750)
Virtualization-based security -- a lighter mode of Hyper-V sans real VMs -- is enabled by default on new installs on recent-enough hardware:

https://techcommunity.microsoft.com/t5/virtualization/virtua...

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Re:WSL2 corrupting Git repositories and shell history by AshamedCaptain on Sunday January 03, 2021 @10:30AM (#25622286)
The link you posted only contains one device and it happens to be an ARM device. Seeing the impact it still has on battery life at least on x86, I really doubt they have enabled it by default. It was not enabled by default on x86 in 2020 at least.
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Re:WSL2 corrupting Git repositories and shell history by smileybarry on Sunday January 03, 2021 @12:09PM (#25623063)
That's just a blog post about the feature being deployed, of course it won't have many examples. Take any PC from the past few years and install Windows 10 x64 on it. It will have VBS enabled and hypervisors that do not support Windows Hypervisor Platform won't work. That's been my experience since at least 2017.

If you click through "capable hardware" to here[1], you'll see the list of requirements for VBS, including:

> Virtualization-based security (VBS) requires the Windows hypervisor, which is only supported on 64-bit IA processors with virtualization extensions, including Intel VT-X and AMD-v.

So it will never be the case on x86/IA32

1: https://docs.microsoft.com/en-us/windows-hardware/design/dev...

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Re:WSL2 corrupting Git repositories and shell history by AshamedCaptain on Thursday January 07, 2021 @06:35AM (#25669883)
Well, I'm asking because my experience is exactly the opposite. I've installed Windows countless times on systems with all the requirements and HyperV is not enabled. The day it starts being enabled, I don't even want to imagine the number of support calls.
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Re:WSL2 corrupting Git repositories and shell history by jrockway on Sunday January 03, 2021 @01:51PM (#25623998)
Do you have a reference to the increased power consumption that running a hypervisor causes? This thread is the first I've heard about it, and I would like to learn more.
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Re:WSL2 corrupting Git repositories and shell history by AshamedCaptain on Thursday January 07, 2021 @06:38AM (#25669897)
No, and I also would like to find some academical test. Try it -- you can even dual boot hypervisor on/off. It's not a small effect. Around 1h extra one on "almost idle" scenarios.
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Re:WSL2 corrupting Git repositories and shell history by ylor on Saturday January 02, 2021 @11:54AM (#25614111)
First I hear of this. Source? Googling for this predictably returned unhelpful results.
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Re:WSL2 corrupting Git repositories and shell history by danieldk on Saturday January 02, 2021 @12:16PM (#25614312)
In VBS environments, the normal NT kernel runs in a virtualized environment called VTL0, while the secure kernel runs in a more secure and isolated environment called VTL1.

https://www.microsoft.com/security/blog/2020/07/08/introduci...

https://docs.microsoft.com/en-us/windows-hardware/design/dev...

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Re:WSL2 corrupting Git repositories and shell history by 10000truths on Saturday January 02, 2021 @10:36AM (#25613462)
Erm, explain? What attack can you do with hardware virtualization enabled that you cannot otherwise do?
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Re:WSL2 corrupting Git repositories and shell history by proactivesvcs on Monday January 04, 2021 @05:47PM (#25639355)
I've read[1] that it can make Meltdown/Spectre attacks possible and thought I'd seen many more reports and discussions about it, but seems I was mistaken.

[1] https://nvd.nist.gov/vuln/detail/CVE-2018-3646

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Re:WSL2 corrupting Git repositories and shell history by h_r on Saturday January 02, 2021 @10:52AM (#25613588)
Are there significant risks from running virtualization locally like this? If so, can you provide any links or elaborate a bit so I can follow up? Most of what I've seen on such vulnerabilities refer to server infrastructure.
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Re:WSL2 corrupting Git repositories and shell history by proactivesvcs on Monday January 04, 2021 @05:48PM (#25639368)
Having searched through my browsing history and some web searches it seems you're right. I do wonder if the move to more virtualisation outside of the server world will open up additional vulnerabilities but it does look like that's where most of the trouble is at the moment.
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Re:WSL2 corrupting Git repositories and shell history by danieldk on Saturday January 02, 2021 @11:20AM (#25613791)
In Windows, enabling virtualization actually reduces attack surface. E.g. it is used to protect against kernel-level malware:

https://www.techrepublic.com/article/how-virtualisation-is-c...

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Re:WSL2 corrupting Git repositories and shell history by proactivesvcs on Monday January 04, 2021 @05:49PM (#25639379)
Yes quite correct. I know some anti-virus engines have been using it for behavioural analysis. I wonder if this will mean more exploits against anti-virus emerge, as with their unpacker routines.
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Re:WSL2 corrupting Git repositories and shell history by mmis1000 on Saturday January 02, 2021 @07:33PM (#25618148)
Well, android simulators do use hardware virtualization. And there is actually many people use them outside of developments.
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