Option Explicit
Option Base 0
'---------------------------------------------------------------------------------------
' Module    : mCopyMemoryASM
' Author    : Karcrack
' Date      : 280710
' Purpose   : A kewl RtlMoveMemory/CopyMemory replacement using ASM :)
'---------------------------------------------------------------------------------------
 
'USER32
Private Declare Function CallWindowProcW Lib "USER32" (ByVal lpCodePointer As Long, Optional ByVal l1 As Long, Optional ByVal l2 As Long, Optional ByVal l3 As Long, Optional ByVal l4 As Long) As Long
 
Private bvCode(20)      As Byte
'{
'    PUSH ESI
'    PUSH EDI
'    MOV EDI,DWORD PTR SS:[ESP+C]
'    MOV ESI,DWORD PTR SS:[ESP+10]
'    MOV ECX,DWORD PTR SS:[ESP+14]
'    REP MOVS BYTE PTR ES:[EDI],BYTE PTR DS:[ESI]
'    POP EDI
'    POP ESI
'    RETN 10
'}
Private bInitialized    As Boolean
 
Public Function ASM_Initialize() As Boolean
    On Error GoTo Initialize_Error
    Dim i               As Long
 
    For i = 0 To 20
        bvCode(i) = CByte(Choose(i + 1, &H56, &H57, &H8B, &H7C, &H24, &HC, &H8B, &H74, &H24, &H10, &H8B, &H4C, &H24, &H14, &HF3, &HA4, &H5F, &H5E, &HC2, &H10, &H0))
    Next i
 
    bInitialized = True
    ASM_Initialize = True
 
    On Error GoTo 0
    Exit Function
Initialize_Error:
    ASM_Initialize = False
End Function
 
Public Sub ASM_CopyMemory(ByVal Source As Long, ByVal Destination As Long, ByVal Length As Long)
    If bInitialized = True Then
        Call CallWindowProcW(VarPtr(bvCode(0)), Destination, Source, Length)
    End If
End Sub
 
'PutMem4 Wrapper
Public Sub ASM_PutMem4(ByVal lLong As Long, ByVal Destination As Long)
    Call ASM_CopyMemory(VarPtr(lLong), Destination, &H4)
End Sub
 
'GetMem4 Wrapper
Public Function ASM_GetMem4(ByVal Source As Long) As Long
    Call ASM_CopyMemory(Source, VarPtr(ASM_GetMem4), &H4)
End Function

Ejemplo:

Private Sub Form_Load()
    Dim x       As Long
    Dim y       As Long
    Dim i       As String
    Dim n       As String
 
    If ASM_Initialize = True Then
        x = &H1337
        Call ASM_CopyMemory(VarPtr(x), VarPtr(y), &H4)
        Debug.Print Hex$(x), Hex$(y)
        y = 0
        Call ASM_PutMem4(x, VarPtr(y))
        Debug.Print Hex$(ASM_GetMem4(VarPtr(x)))
        Debug.Print Hex$(x), Hex$(y)
        i = "KARCRACK_ES_GUAY!!!!!!!"
        n = Space$(Len(i))
        Call ASM_CopyMemory(StrPtr(i), StrPtr(n), LenB(i))
        Debug.Print i
        Debug.Print n
    End If
End Sub

Saluuudos

Exelente Karcrack! Vas a tener que sacar un libro con tanto code interesante!    

Edit:

Alguien podria comentar cada linea del shellcode, aver si logro entenderlo?
'{
'    PUSH ESI 'variable?
'    PUSH EDI 'variable?
'    MOV EDI,DWORD PTR SS:[ESP+C] 'parametro 1?
'    MOV ESI,DWORD PTR SS:[ESP+10] 'parametro 2?
'    MOV ECX,DWORD PTR SS:[ESP+14] 'parametro 3?
'    REP MOVS BYTE PTR ES:[EDI],BYTE PTR DS:[ESI] 'esto mueve la data en mem?
'    POP EDI 'fee a var?
'    POP ESI 'fee a var?
'    RETN 10 'retorno
'}

Soy un completo indio en ASM, solo sé un par de instrucciones $:, es parcialmnte correcto lo que puse?

Eso es prescindible no?¿

DoEvents¡!

A eso me referia...

DoEvents¡!