Encryption password stopped working for guest OS

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Pinkolik
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Joined: 4. Apr 2021, 08:43

Encryption password stopped working for guest OS

Post by Pinkolik »

Hello everyone!
So my problem is that today my VirtualBox guest OS with Linux Mint installed stopped letting me in because "the password is incorrect", although I'm 100% sure it is correct because I used it yesterday, I also copied and pasted it, nothing worked for me.
I did some research in hope that I can fix this problem myself and found this topic [sorry I can't post links yet]. The problem is very similar, and, just like in my case that user had Whonix OS configuration imported recently, so I think it's connected somehow. But in my case I haven't encrypted any of Whonix OSes, I only have my Mint OS encrypted.
I have a lot of important data on that VM, so I really hope that there's something that can be done.
I'll attach logs, and VBox config and VM config.
P.S. Okay, I can't post links yet becuase I'm a member less than a day. I will post a link to that post tomorrow. It's called "[Solved] Encryption password for guest OS no longer working" you can search it yourself.
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fth0
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Re: Encryption password stopped working for guest OS

Post by fth0 »

The KeyId and KeyStore attributes do exist in the Mint.vbox file as expected, so you probably don't have the same problem as in [Solved] Encryption password for guest OS no longer working.

Your VBox.log file indicates that you've enabled Hyper-V on your host, and that can interfere with cryptographic operations. Please read and follow HMR3Init: Attempting fall back to NEM (Hyper-V is active).
Pinkolik
Posts: 6
Joined: 4. Apr 2021, 08:43

Re: Encryption password stopped working for guest OS

Post by Pinkolik »

Hello, fth0. Thanks for a quick reply.
I tried your instruction and disabled Hyper-V - still same result though. I always had that green turtle in the corner so I don't think that was the case.
Also, another thing came to my mind, the evening prior everything stopped working I had installed AESCrypt software. How do you think could this be the reason?
scottgus1
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Re: Encryption password stopped working for guest OS

Post by scottgus1 »

One thing to clarify:
Encryption password stopped working for guest OS
Pinkolik wrote:my VirtualBox guest OS with Linux Mint installed stopped letting me in because "the password is incorrect"
Is this encryption password in a Virtualbox textbox that comes up before the VM OS even boots, for Virtualbox disk encryption? Or has the VM started booting then the box comes up in a Linux Mint textbox?
Pinkolik
Posts: 6
Joined: 4. Apr 2021, 08:43

Re: Encryption password stopped working for guest OS

Post by Pinkolik »

It's the textbox that comes up before OS boots. It looks like this
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fth0
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Re: Encryption password stopped working for guest OS

Post by fth0 »

Pinkolik wrote:Also, another thing came to my mind, the evening prior everything stopped working I had installed AESCrypt software. How do you think could this be the reason?
The VirtualBox Disk Encryption uses AES in XTS mode, so it could be the reason. If you uninstall the AESCrypt software, does the problem persist?
scottgus1 wrote:Is this encryption password in a Virtualbox textbox that comes up before the VM OS even boots, for Virtualbox disk encryption?
Yes. Search the VBox.log file for all lines containing "DEK", and note the timestamp of the last match. ;)
Pinkolik
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Re: Encryption password stopped working for guest OS

Post by Pinkolik »

fth0 wrote:If you uninstall the AESCrypt software, does the problem persist?
I've just uninstalled it and rebooted and the problem still persists. I also tried checking registry for "AESCrypt" entries but nothing was found.
fth0
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Re: Encryption password stopped working for guest OS

Post by fth0 »

Does your password contain characters not available in the 7-bit ASCII character set?

If the answer is no and if you'd provide me with the password, I'd try if it would be accepted on another host.
Pinkolik
Posts: 6
Joined: 4. Apr 2021, 08:43

Re: Encryption password stopped working for guest OS

Post by Pinkolik »

fth0 wrote:Does your password contain characters not available in the 7-bit ASCII character set?

If the answer is no and if you'd provide me with the password, I'd try if it would be accepted on another host.
Hey, fth0, sorry for such a delay.
No, my password doesn't contain characters that are not available in the 7-bit ASCII character set.
And I'm not sure I understand what do you want to try with my password?
I know that it had been working for a couple of weeks correctly and the suddenly stopped, so I think the password is not the case.
Pinkolik
Posts: 6
Joined: 4. Apr 2021, 08:43

Re: Encryption password stopped working for guest OS

Post by Pinkolik »

Is there any workaround?
I think I can live without this VM but I need to get important files from there. Maybe I can use some kind of Linux LiveCD software to boot from it and extract needed files?
fth0
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Re: Encryption password stopped working for guest OS

Post by fth0 »

Pinkolik wrote:And I'm not sure I understand what do you want to try with my password?
Using the KeyID and KeyStore from the Mint.vbox file, I could verify the password. If it was accepted, I'd perhaps suspect keyboard related problems on your side, and if it wasn't accepted, you'd know that there is no chance of matching this KeyStore and the password.

BTW, did you perhaps rename the VM in the past?
fth0
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Re: Encryption password stopped working for guest OS

Post by fth0 »

Pinkolik wrote:Hello. No, I did not rename my VM in the past.
And here's my password:
[...]
Thank you for providing the password. First of all, I've verified that I can encrypt and decrypt a new VDI file with this password, which indicates that VirtualBox has no problem with any character used in the password (as expected).

Then I checked if VirtualBox is able to decrypt the KeyStore from Mint.vbox with this password, but unfortunately it is not. This indicates that whatever error happened was probably in the past. Do you have backups of the Mint.vbox or VBox.log files to check if the KeyStore information has changed?

I can make a wild guess what possibly may have happened: Hyper-V was active on your host, and there have been other problems with cryptographic operations in combination with VirtualBox in the past. Check if your host got Windows updates in the previous days, and try if a rollback (and reenabling Hyper-V with bcdedit /set hypervisorlaunchtype auto) solves your problem.
Pinkolik wrote:Is there any workaround?
Unfortunately not (otherwise the disk encryption wouldn't make much sense): The VDI file is encrypted with a DEK (Data Encryption Key), which is securely stored in the (1) KeyStore, and it can only be recovered with the (2) password and a (3) software algorithm. At least one of those three items does not match.
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