VBA解析VBAProject 06——清除VBA工程密码

2020-10-27 10:29:39 浏览数 (1)

如果你收到过一些这样的Excel文件，文件里有VBA代码，实现了很好的功能，可是作者却对VBA工程进行了加密，你可能会非常希望查看到里面的VBA代码。

会想到的最直接的办法当然就是要到密码，可这个一般做不到，这个时候有什么办法能够查看VBA代码呢？

前面介绍的提取模块代码可以做到，这里再介绍一种直接清除密码的功能。

VBAProject工程里面，一定会有个数据流PROJECT，这个文件提取后，得到的内容大致如下：

代码语言：javascript复制
ID="{7A581A9B-0F9A-480B-8C0A-1C59D52CAB04}"
Document=ThisWorkbook/&H00000000
Document=Sheet1/&H00000000
Module=MMain
Module=MTestStack
HelpFile=""
Name="vbapSpaceTest"
HelpContextID="0"
VersionCompatible32="393222000"
CMG="A4A64B844D9151915191519151"
DPB="B5B75AB77AC97BC97BC9"
GC="C6C429A22BA23DA33DA3C2"

[Host Extender Info]
&H00000001={3832D640-CF90-11CF-8E43-00A0C911005A};VBE;&H00000000

[Workspace]
ThisWorkbook=0, 0, 0, 0, C
Sheet1=0, 0, 702, 415, 
MMain=25, 25, 756, 571, 
MTestStack=275, 275, 1435, 844, Z

VBAProject工程是否设置了密码，信息就保存在了这个数据流中，只需要把下面的内容清除掉就可以了：

代码语言：javascript复制
CMG="A4A64B844D9151915191519151"
DPB="B5B75AB77AC97BC97BC9"
GC="C6C429A22BA23DA33DA3C2"

至于为什么可以看下官方的资料。

所以，知道了这样能够清除密码，我们要做的只是改写一个复合文档的数据流就可以了：

代码语言：javascript复制
'清除vba工程密码
'清除CMG=" | DPB=" | GC="
'清除VBA工程密码
'Return     返回出错信息
Function UnProtectProject() As String
    Dim ret As String
    Dim b() As Byte
    ret = cf.GetStream(PrePath & "PROJECT", b)
    If VBA.Len(ret) Then
        UnProtectProject = ret
        Exit Function
    End If
    
    Dim strSrc As String
    strSrc = VBA.StrConv(b, vbUnicode)
    
    Dim arr(2) As String
    arr(0) = "CMG="""
    arr(1) = "DPB="""
    arr(0) = "GC="""
    Dim i As Long
    Dim index As Long, index2 As Long
    Dim strtmp As String
    Dim flag As Boolean
    
    flag = False
    For i = 0 To 3 - 1
        index = VBA.InStr(strSrc, arr(i))
        If index Then
            flag = True
            index2 = VBA.InStr(index, strSrc, vbNewLine)
            If index2 Then
                strtmp = VBA.Mid$(strSrc, index, index2 - index   2)
                strSrc = VBA.Replace(strSrc, strtmp, "")
            Else
                UnProtectProject = "CVBAProject: UnProtectProject没有找到ODOA"
                Exit Function
            End If
        End If
    Next
    If Not flag Then
        UnProtectProject = "CVBAProject: 没有设置VBA工程密码"
        Exit Function
    End If
    
    b = VBA.StrConv(strSrc, vbFromUnicode)
    ret = cf.ReWriteStream(PrePath & "PROJECT", b)
    If VBA.Len(ret) Then
        UnProtectProject = ret
        Exit Function
    End If
End Function

另外再分享一种可以直接查看带密码的VBAProject的方法：

代码语言：javascript复制
'复制内存
Private Declare Sub MoveMemory Lib "kernel32" Alias "RtlMoveMemory" (Destination As Long, Source As Long, ByVal Length As Long)
'修改虚拟保护
Private Declare Function VirtualProtect Lib "kernel32" (lpAddress As Long, ByVal dwSize As Long, ByVal flNewProtect As Long, lpflOldProtect As Long) As Long
'获取一个应用程序或动态链接库的模块句柄
Private Declare Function GetModuleHandleA Lib "kernel32" (ByVal lpModuleName As String) As Long
'返回函数地址
Private Declare Function GetProcAddress Lib "kernel32" (ByVal hModule As Long, ByVal lpProcName As String) As Long

'该函数根据对话框模板资源创建一个模态的对话框。在显示对话框之前，函数把一个应用程序定义的值作为WM_INITDIALOG消息的IParam参数传到对话框过程,应用程序可用此值来初始化对话框控制。
'Private Declare Function DialogBoxParam Lib "user32" Alias "DialogBoxParamA" (ByVal hInstance As Long, hDialogTemplate As DLGTEMPLATE, ByVal hWndParent As Long, ByVal lpDialogFunc As Long, ByVal dwInitParam As Long) 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 '获得函数地址
    GetPtr = Value
End Function
Public Sub RecoverBytes() '若已经Hook，则恢复原API开头的6字节，也就是恢复原来函数的功能
    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
    'VBE6.dll调用DialogBoxParamA显示VB6INTL.dll资源中的第4070号对话框（就是输入密码的窗口）
    '若DialogBoxParamA返回值非0，则VBE会认为密码正确，所以我们要hook DialogBoxParamA函数
    pFunc = GetProcAddress(GetModuleHandleA("user32.dll"), "DialogBoxParamA")
    
    '标准api hook过程之一：修改内存属性，使其可写
    If VirtualProtect(ByVal pFunc, 6, &H40, OriginProtect) <> 0 Then
    
    '标准api hook 过程之二：判断是否已经hook，看看API的第一个字节是否为&H68
    '若是则说明已经hook
        MoveMemory ByVal VarPtr(TmpBytes(0)), ByVal pFunc, 6
        If TmpBytes(0) <> &H68 Then
            '标准api hook 过程之三：保存原函数开头字节，这里是6个字节，以备后面恢复
            MoveMemory ByVal VarPtr(OriginBytes(0)), ByVal pFunc, 6
            '用Addresof获取MyDialogBoxParam，这里我们写一个函数
            'GetPtr作用仅仅是返回Addressof MyDialogBoxParam的值，从而实现将
            'MyDialogBoxParam的地址赋给p的目的
            p = GetPtr(AddressOf MyDialogBoxParam)
            '标准的api hook过程之四：组装API入口的新代码
            'HookBytes组成如下汇编
            'push MyDialogBoxParam的地址
            'ret
            '作用是跳转到MyDialogBoxParam函数
            HookBytes(0) = &H68
            MoveMemory ByVal VarPtr(HookBytes(1)), ByVal VarPtr(p), 4
            HookBytes(5) = &HC3
            
            ''标准的api hook过程之五：用HookBytes的内容改写API前6个字节
            MoveMemory ByVal pFunc, ByVal VarPtr(HookBytes(0)), 6
            '设置hook成功标准
            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
        '有程序调用DialogBoxParamA装入4070号对话框，这里就我们直接返回1，让VBE以为密码正确了
        MyDialogBoxParam = 1
    Else
        '有程序调用DialogBoxParamA，但装入的不是4070号对话框，这里我们调用RecoverBytes函数恢复原来函数的功能，再进行原来的函数
        RecoverBytes
        MyDialogBoxParam = DialogBoxParam(hInstance, pTemplateName, hWndParent, lpDialogFunc, dwInitParam)
        '原来的函数执行完毕，再次hook
        Hook
    End If
End Function

这个是在网上看到的，至于原理其实不大理解。

vba 编程算法

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