Remko Weijnen's Blog (Remko's Blog)

About Virtualization, VDI, SBC, Application Compatibility and anything else I feel like

Yesterday I was working with an Excel document that contained Combobox form controls.

I wanted to count the number of cells containing a particular value using the COUNTIF formula. However the count returned 0 because the LinkedCell property of the Combobox was not set to the Cell that contained the Combobox.

To set the LinkedCell Ctrl-Click the Combobox to select it, right-click and select Format Control. Then set the correct Cell in the Cell link field:

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My sheet contained about 150 Comboboxes, so obviously I was going to do this using a script. I couldn’t find anything useful with Google so I wrote my own Macro.

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Excel 2010 multi-threaded calculation

Excel 2007 IconI was just browsing through the Options tab in Excel 2010 when I noticed the following setting:

image

 

This feature was introduced in Excel 2007.
In the default settings, multi-threaded calculation is Enabled with "Use all processors on this computer".

On a physical desktop this would be the preferred setting since it will make formula calculation as fast as possible.

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  • 10 Comments
  • Filed under: General
  • Session freeze when starting Excel

    Environment
    Windows 2003 Enterprise (32 bit), Citrix XenApp 5, RES Workspace Manager 2011, McAfee VirusScan Enterprise 8.7.0i.

    Problem
    When a opening an Excel workbook from Sharepoint the whole session freezes.

    I asked the user to open an Excel workbook from Sharepoint and I noticed the following popup:

    Some files can harm your computer. If the file information looks suspicious or you do not fully trust the source, do not open the file | You are opening the following file: | File name: My Workbook.xls | From: Sharepoint

    So my first thought was that the user somehow clicked this message to the background and IE was waiting for a response.

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    The XLSploit explained

    Recently I published a Proof of Concept that showed it was possible to launch unauthorized processes with both AppSense Application Manager and RES Workspace Manager.

    Although I didn’t test Microsoft Applocker I have no doubt at all that we couldn’t bypass it.

    imageI have named my Proof of Concept the XLSploit because I am using Excel as a trampoline. I choose Excel because this is generally a trusted process and VBA offers access to the Windows API that is needed.

    After publishing the XLSploit I have talked to both RES and AppSense and not that they both have a response to my Proof of Concept, I consider it safe to tell a little more about how it works.

    If you are merely interested in stopping the XLSploit, please scroll down to the end of the article.

    (more…)

  • 3 Comments
  • Filed under: General
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