Warning ⚠️

THERE IS 0 ANTI-CHEAT PROTECTIONS IN THIS PROJECT, PLEASE USE A BASE DRIVER THAT IS ALREADY UNDETECTED, THIS IS JUST A CONCEPT PROJECT.

Explenation

The exploit involves scanning for specific signatures in kernel memory, and modifying processor affinity masks to prevent NMIs from executing. This approach employs techniques to avoid detection and tracing.

Function

I do a signature scan for NMI_IN_PROGRESS using 23H2 Signatures for NMI_IN_PROGRESS and import the struct as (PKNMI_HANDLER_CALLBACK) for easy DKOM Modification.

	// nmi_in_progress function (signature)
	char NmiSignature[] = "\x81\x25\x00\x00\x00\x00\x00\x00\x00\x00\xB9\x00\x00\x00\x00"; // use XOR to encrypt this (will get sig scanned by ac)
	char NmiSignatureMask[] = "xx????????x????"; // use XOR to encrypt this (will get sig scanned by ac)
	uintptr_t nmi_in_progress = modules::find_pattern(ntos_base_address,
		NmiSignature,
		NmiSignatureMask);

    return reinterpret_cast<PKNMI_HANDLER_CALLBACK>(nmi_in_progress);

I then after importing the structure loop through the KiNmiCallbackList and change the process affinity of the specific assets to prevent NMI Execution.

PKNMI_HANDLER_CALLBACK KiNmiCallbackListHead = nullptr;
extern "C" NTSTATUS PreventNMIExecution() {
	KiNmiCallbackListHead = SigscanKiNmiCallbackListHead();
	PKNMI_HANDLER_CALLBACK CurrentNMI = KiNmiCallbackListHead;
	while (CurrentNMI) {
		uint8_t* nmi_in_progress = reinterpret_cast<uint8_t*>(KiNmiCallbackListHead);

		while (*nmi_in_progress != 0x48) {
			++nmi_in_progress;
		}

		nmi_in_progress = reinterpret_cast<uint8_t*>(reinterpret_cast<intptr_t>(nmi_in_progress) + 3);

		auto irql = KfRaiseIrql(0); // Use Udman Spoof to not get logged by this

		ULONG cores = KeQueryActiveProcessorCount(NULL); // Use Udman Spoof to not get logged by this

		for (auto i = 0ul; i < cores; ++i) {
			KeInterlockedSetProcessorAffinityEx((PKAFFINITY_EX)nmi_in_progress, i); // Use Udman Spoof to not get logged by this
			InterlockedBitTestAndSet64(reinterpret_cast<LONG64*>(nmi_in_progress), i);
		}

		KeLowerIrql(irql); // Use Udman Spoof to not get logged by this

		CurrentNMI = CurrentNMI->Next;
	}
	return STATUS_SUCCESS;
}

EAC NMI Walker

BOOLEAN EAC::NmiCallbackRoutine( PVOID Context, BOOLEAN Handled )
{
	auto* callback_context = reinterpret_cast< EAC_NMI_CALLBACK_CONTEXT* >( Context );
	
	auto* data = &callback_context->data_blocks[ KeGetCurrentProcessorNumberEx( NULL ) ];
	
	if ( !data->gdtr_value.base )
	{
		const auto* current_thread = PsGetCurrentThread();
		__sgdt( &data->gdtr_value );
		data->thread_id = PsGetCurrentThreadId();
		data->thread_process_id = PsGetThreadProcessId( current_thread );
		data->thread_SystemCallNumber = current_thread->SystemCallNumber;
		data->thread_StartAddress = current_thread->StartAddress;
		data->thread_StackLimit = current_thread->StackLimit;
		data->thread_StackBase = current_thread->StackBase;
		data->pcr_HalReserved_8 = KeGetPcr()->HalReserved[ 8 ];
		data->cr3_value = __readcr3();
		data->stack_copy_number_of_bytes = 1024;
		std::memcpy( &data->stack_copy, _AddressOfReturnAddress(), 1024 );
		_InterlockedIncrement( &callback_context->counter );
	}
	
	return TRUE;
}
// Not My Code

Notes

You will need to add & use (x) as this is detected by default for Tracing & Trace Calls (If using standard NtLoad or standard Service Running).

Udman Spoof Calls to avoid tracing
XOR for strings & signatures
SpoofCall & SpoofFunc Functions

PatchGuard & HVCI

This will trigger PatchGuard Protections and if trying to bypass PatchGuard will trigger HyperGuard High-Level Protections and if you also use HVCI (say in valorant/VGK) This will trigger a BSOD or block the requests to modify the NMI List and nothing will change. I have figured these issues out on my own for my personal driver but if you have a bypass for PatchGuard / HyperGuard and dont use HVCI Protection (for BE/EAC) this will work.

Contact

If you want to contact me in regards of my work or projects my discord is -> _chisla, Please do not message me for Issues or Learning/Studying I am not a teacher.