Excel VBA – Alternatives to Easily Cracked Project Passwords

excelpassword-protectionpasswordsvba

Now that I know that there is an easy workaround to the standard way of locking and password-protecting VBA code, I'd like to move on to more effective ways of protecting code. I am to deliver an Excel-based tool to a client, but would like something more than simple annoyance-type protection that will only deter the laziest of hackers.

Are there any options in Excel-VBA, or do we really have to compile a separate application and forget about our Excel-based interface?

Best Answer

The easiest and most efficient way is to move your VBA code to a VB6 compiled Com/automation addin.

Or you may want to consider a .Net (with obfuscator) solution if performance is not important.

How it works

I will try my best to explain how it works - please excuse my English.

The VBE will call a system function to create the password dialog box.
If user enters the right password and click OK, this function returns 1. If user enters the wrong password or click Cancel, this function returns 0.
After the dialog box is closed, the VBE checks the returned value of the system function
if this value is 1, the VBE will "think" that the password is right, hence the locked VBA project will be opened.
The code below swaps the memory of the original function used to display the password dialog with a user defined function that will always return 1 when being called.

Using the code

Please backup your files first!

Open the file(s) that contain your locked VBA Projects

Create a new xlsm file and store this code in Module1

code credited to Siwtom (nick name), a Vietnamese developer

Option Explicit

Private Const PAGE_EXECUTE_READWRITE = &H40

Private Declare Sub MoveMemory Lib "kernel32" Alias "RtlMoveMemory" _
        (Destination As Long, Source As Long, ByVal Length As Long)

Private Declare Function VirtualProtect Lib "kernel32" (lpAddress As Long, _
        ByVal dwSize As Long, ByVal flNewProtect As Long, lpflOldProtect As Long) As Long

Private Declare Function GetModuleHandleA Lib "kernel32" (ByVal lpModuleName As String) As Long

Private Declare Function GetProcAddress Lib "kernel32" (ByVal hModule As Long, _
        ByVal lpProcName As String) As Long

Private Declare Function DialogBoxParam Lib "user32" Alias "DialogBoxParamA" (ByVal hInstance As Long, _
        ByVal pTemplateName As Long, ByVal hWndParent As Long, _
        ByVal lpDialogFunc As Long, ByVal dwInitParam As Long) As Integer

Dim HookBytes(0 To 5) As Byte
Dim OriginBytes(0 To 5) As Byte
Dim pFunc As Long
Dim Flag As Boolean

Private Function GetPtr(ByVal Value As Long) As Long
    GetPtr = Value
End Function

Public Sub RecoverBytes()
    If Flag Then MoveMemory ByVal pFunc, ByVal VarPtr(OriginBytes(0)), 6
End Sub

Public Function Hook() As Boolean
    Dim TmpBytes(0 To 5) As Byte
    Dim p As Long
    Dim OriginProtect As Long

    Hook = False

    pFunc = GetProcAddress(GetModuleHandleA("user32.dll"), "DialogBoxParamA")


    If VirtualProtect(ByVal pFunc, 6, PAGE_EXECUTE_READWRITE, OriginProtect) <> 0 Then

        MoveMemory ByVal VarPtr(TmpBytes(0)), ByVal pFunc, 6
        If TmpBytes(0) <> &H68 Then

            MoveMemory ByVal VarPtr(OriginBytes(0)), ByVal pFunc, 6

            p = GetPtr(AddressOf MyDialogBoxParam)

            HookBytes(0) = &H68
            MoveMemory ByVal VarPtr(HookBytes(1)), ByVal VarPtr(p), 4
            HookBytes(5) = &HC3

            MoveMemory ByVal pFunc, ByVal VarPtr(HookBytes(0)), 6
            Flag = True
            Hook = True
        End If
    End If
End Function

Private Function MyDialogBoxParam(ByVal hInstance As Long, _
        ByVal pTemplateName As Long, ByVal hWndParent As Long, _
        ByVal lpDialogFunc As Long, ByVal dwInitParam As Long) As Integer
    If pTemplateName = 4070 Then
        MyDialogBoxParam = 1
    Else
        RecoverBytes
        MyDialogBoxParam = DialogBoxParam(hInstance, pTemplateName, _
                           hWndParent, lpDialogFunc, dwInitParam)
        Hook
    End If
End Function

Paste this code under the above code in Module1 and run it

Sub unprotected()
    If Hook Then
        MsgBox "VBA Project is unprotected!", vbInformation, "*****"
    End If
End Sub

Come back to your VBA Projects and enjoy.

Best Answer

Related Solutions

VBA Excel – How to Remove Password from VBA Project

Excel VBA – How to Crack the Password on an Excel VBA Project

How it works

Using the code

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