Intro to VBA

• Visual Basic for Applications
• Using this you can extend excel.
  • This provides a powerful tool, you can make excel do new things
  • This provides a dangerous security hole, you can make excel do new things.
  • See
    • Microsoft Article
    • Here is a useful article
  • Apparently macros can use a shell to execute commands.
  • This opens the possibility to do things like
    • The Melissa virus
      • Opened the user's address book.
      • Extracted the first 50 entries (email addresses)
      • Mailed a copy of the infected document to these users.
      • This was a Denial of Service Attack (DOS).
      • The Wikipedia page has a cool story.
    • The WAZZU virus
      • Embedded a copy of the virus in the default document file.
      • Then would randomly move words around in the file.
      • Or insert the word Wazzu
    • Here is a more scary article.
    • Norton has an article describing macro viruses.
• Levels of Macro Security
  • File to Options To Trust Center.
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  • You probably want to disable everything until you need to change this.
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• Workbooks with macros
  • Saving a workbook with macros can not be in .xlsx format
  • Save as a Excel Macro-Enabled Workbook
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  • This creates an .xlsm file
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• Enabling the Developer Tab
  • The developer tab is probably disabled at this point.
  • Right click on any tab and select Customize the Ribbon
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  • Check the box next to the developer tab.
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