The context: I already use FDE on my system drive (strong cipher, long unguessable password, etc.), but on the off-chance that my password is stolen or my computer is cold-booted, I want to prevent any potential adversary (assume one who’s skilled and resourceful, such as a hacker with knowledge of computer forensics) from learning about my more private activities on my computer – records of visiting certain websites, handling sensitive files (such as protected work documents), private communications, and so on.
The setup: I have VirtualBox installed on my (Host) machine using the standard installer and settings. I have a VM/Guest OS for those aforementioned private activities so that traces aren’t left on the Host (or at least aren’t immediately obvious – no “Recent Files” entries, browser history, etc). The Guest VDI (virtual hard drive) is stored in a separate, encrypted partition (which uses a different password from my Host’s drive).
(In case it may be relevant, the Host OS is Windows 8.1 Pro; the Guest OS is Windows 7 Ultimate.)
As I understand it, this setup means that when VirtualBox is shut down, the Guest OS is inaccessible without the password to its encrypted partition; however, VirtualBox may leave traces of its operation and my activities within it on the Host OS (such as log files, temporary files, registry entries, etc.). I do not know what information VirtualBox actually stores about the contents of its VMs or what users do with them, so I’m assuming the worst-case scenario: records of files opened and modified, websites visited, people communicated with, etc. (I know this is likely paranoid, but I’d rather be safe than sorry.)
My question: Is it possible to install or configure VirtualBox in such a way that it doesn’t leave any aforementioned traces (logs, temporary files, registry entries, etc.) on the Host OS drive? To be clear, I’m concerned less with hiding the existence of VirtualBox or the VM, and more with concealing the what I do within that VM when it’s running. If I can accomplish the latter, I’ll be satisfied.
One idea I had is to use Portable-VirtualBox, which claims to force VirtualBox to use relative paths for its files so that they’re all stored in the same directory Portable-VirtualBox is installed in (instead of “<User>\AppData” and so on). Using this in a VeraCrypt volume would be ideal for me, but I haven’t tested it yet, and at any rate I don’t know what traces Portable-VirtualBox may still leave behind on the Host OS.
(As to why I don’t use a bootable live system such as Tails, I’d prefer to still be able to use my regular OS at the same time without needing to shut one down to boot the other, hence why I want to use a VM if at all possible. I plan to purchase a separate computer in the future for all this, at which point a VM will no longer be necessary, but that’s not for a while.)
Please let me know if anything about my question is unclear. Thanks for any thoughts or advice.