Credit

• cr4sh - cr4sh has done something like this a few years back. A link to it can be found here.
• btbd - offering suggestions and providing input... also stole utils.c/utils.h 👍

Voyager - A Hyper-V Hacking Framework For Windows 10 x64 (AMD & Intel)

Voyager is a project designed to offer module injection and vmexit hooking for both AMD & Intel versions of Hyper-V. This project works on all versions of Windows 10-x64 (2004-1507).

bootmgfw.efi

bootmgfw.ImgArchStartBootApplication between windows versions 2004-1709 is invoked to start winload.efi. A hook is place on this function in order to install hooks in winload.efi before winload.efi starts execution.

On windows 1703-1511 the symbol/name is different but parameters and return type are the same: bootmgfw.BlImgStartBootApplication.

winload.efi

winload.efi between Windows 10-x64 versions 2004-1709 export a bunch of functions. Some of those functions are then imported by hvloader.dll such as BlLdrLoadImage. Older versions of windows 10-x64 (1703-1507) have another efi file by the name of hvloader.efi. Hvloader.efi contains alot of the same functions that are inside of winload. You can see that Microsoft simplified hvloader.efi in later versions of Windows 10-x64 by making winload export the functions that were also defined in hvloader.efi.

If you look at the project you will see hvloader.c/hvloader.h, these contain the hooks that are placed inside of hvloader and are installed from a hook inside of winload. 1703-1507 requires an extra set of hooks to get to where Hyper-v is loaded into memory.

hvloader.efi

Hvloader.efi contains alot of the same functions that can be found inside of winload.efi as explained in the section above. In Windows 10-x64 versions spanning 1703-1507, Hyper-v is not loaded from a function found in winload.efi but instead of the same function found inside of hvloader.efi. These functions are hvloader.BlImgLoadPEImageEx and hvloader.BlImgLoadPEImageFromSourceBuffer.

Usage

Please enable hyper-v in "turn windows features on or off". Then run launch.bat as admin, this will mount the EFI partition and move some files around then reboot you. Voyager is designed to recover from a crash. The first thing Voyager will do when executed is restore bootmgfw on disk. If any complications occur during boot you can simply reboot.