CODEWITHSUNDEEP
vbaexcel
Karel Jansen
Karel Jansen

Reputation: 63

Security - How to secure more

I'm currently developing a Excel document for my clients and its really important that the security on the VBA is really good protected. It's not the intention that they can look into this document. So i was searching how i could bypass the VBA Password and i found a Macro that overuns the old password.

My Question: Is there a way to disable the macro below?

Module 1:

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

Module 2 (and run this one)

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

Upvotes: 4

Views: 451

Answers (1)

Doug Coats
Doug Coats

Reputation: 7107

1) the code doesnt work on newer versions of excel

2) HEx Editors will make you cry Excel VBA Password via Hex Editor

3) @TimWilliams comment also applies

Upvotes: 4

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