In x64 systems, Microsoft has introduced new protection against kernel-mode hooking and patching called KPP, or PatchGuard. This protection disables any patching of the SSDT, the IDT, the Global Descriptor Table (GDT), and the core kernel code. It doesn't allow the usage of kernel stacks beyond what was allocated by the kernel itself.
Additionally, Microsoft allows only signed drivers to be loaded in the x64 systems, except for situations when the system is running in test mode or driver signature enforcement is disabled.
KPP received lots of criticism from antivirus and firewall vendors when it was first introduced because SSDT hooking and other hooking types were heavily used in multiple security products. Microsoft has created a new API to help antivirus products replace their hooking methods.
Although multiple ways of bypassing PatchGuard have been documented, for the last several years, Microsoft has released only a few major updates to deal with...
