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Password security problem: view of the hiden worksheet in xlsm and xlsx file !?
Hello,
if you have an excel file of the type xlsm and if you protect the VBA code with a password then you disable the user from seeing not only the code but also from seeing the structure of worksheets, among them especially the 'very hiden' worksheets too. An over inquisitive user can but save the VBA password protected xlsm file as an xlsx file. In such a case the user besides he lose the VBA code he get the access to all of the worksheets where he can then change the properties and finally he get the access to the data of the before hiden worksheets. Is there any way to avoid to make user possible to view the data he shoud not see? Ivan |
#2
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Password security problem: view of the hiden worksheet in xlsm and
There is absolutely no way to effectively protect data within an XL
spreadsheet. Any passwords can be broken (some are more difficult than others but all can be broken). Very hidden sheets can easily be unhidden with very simple code. In short if you are worried about security XL is not a good platform to choose. Run this code against any workbook to view all sheets dim wks as worksheet for each wks in activeworkbook.Worksheets wks.visible = xlsheetvisible next wks (it misses xl4 macro sheets but that is easy to view also if you want) If the workbook is protected then there is simple code that you can download to hack the password. -- HTH... Jim Thomlinson "Ivan" wrote: Hello, if you have an excel file of the type xlsm and if you protect the VBA code with a password then you disable the user from seeing not only the code but also from seeing the structure of worksheets, among them especially the 'very hiden' worksheets too. An over inquisitive user can but save the VBA password protected xlsm file as an xlsx file. In such a case the user besides he lose the VBA code he get the access to all of the worksheets where he can then change the properties and finally he get the access to the data of the before hiden worksheets. Is there any way to avoid to make user possible to view the data he shoud not see? Ivan |
#3
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Password security problem: view of the hiden worksheet in xlsm and xlsx file !?
Searched by Google I saw (but I don't see the same in my Outlook Express ?)
that Jim Thomlinson have replied to my question and he has stressed that Excel is completly unsafe and that it is always possible to break into the code and into the structure of worksheets. I agree with his thinking. However within bounds of practicability I wanted to secure my workbook on a such way to make it impossible the entry into the code and the view into the structure of worksheets for all ordinary users. I think I found one way how to prevent user from seeing the data of the very hiden worksheets in the case when the user save the excel xlsm file as the xlsx one. I can use the event BeforClose of the worbook in such case. In the code of BeforClose event it must be asked if the ActiveWorkbook.FileFormat is equal 52 ( i.e. format is xlsm) and if this number is not 52 all sheets with confidential data must be cleared: If ActiveWorkbook.FileFormat < 52 then Sheets("NameOfSheet").Select Cells.Select Selection.ClearContests ActiveWorkbook.Save End If Ivan "Ivan" wrote in message ... Hello, if you have an excel file of the type xlsm and if you protect the VBA code with a password then you disable the user from seeing not only the code but also from seeing the structure of worksheets, among them especially the 'very hiden' worksheets too. An over inquisitive user can but save the VBA password protected xlsm file as an xlsx file. In such a case the user besides he lose the VBA code he get the access to all of the worksheets where he can then change the properties and finally he get the access to the data of the before hiden worksheets. Is there any way to avoid to make user possible to view the data he shoud not see? Ivan |
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