Excel破解VBA项目的密码保护

Excel破解VBA项目的密码保护

原理

VBE的密码保护是提供了一个密码窗口，用于输入保护密码，校验输入的密码是否正确
想要破解密码，即通过修改电脑内存中返回校验密码的结果为1即可

  • VBE 将调用一个系统函数来创建密码对话框。
  • 如果用户输入正确的密码并单击”确定”，则此函数返回 1。
  • 如果用户输入错误的密码或单击”取消”，则此函数返回 0。
  • 对话框关闭后，VBE检查系统函数的返回值
  • 如果该值为 1，则 VBE 将”认为”密码正确，因此将打开锁定的 VBA 项目。
  • 我们可以通过实现将用于显示密码对话框的原始函数的内存与用户定义的函数交换，使该函数在被调用时将始终返回 1。

实现

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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

示例

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Sub Unprotected()
    If Hook Then
        MsgBox "VBA Project 解码成功!", vbInformation, "*****"
    End If
End Sub

引用