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BBB warns: Don’t fall for this ‘macros’ scam to send malware to computer

Thursday, January 31, 2013 - 9:30 am

This is a consumer advice column written by the Better Business Bureau of Northern Indiana. It appears Thursdays in Business.

A scam that promises unlimited Sudoku puzzles can be tempting this time of year. With more indoor activity, or hanging out at the airport, you may find puzzles something entertaining and relaxing to do.

The scam works this way: You receive a Microsoft Excel spreadsheet that promises to automatically generate Sudoku puzzles. However, when you open the file and try to create a new puzzle, you get a message that you need to “enable macros” by disabling the software's security setting. By doing this, you will allow the malware to run on your computer. It will scan your system and send an email with details about your machine, according to computer security blog Naked Security.

What are macros? If you perform a task repeatedly in Microsoft Excel (or another Microsoft Office program), you can speed up your work by automating the task with a macro, a series of commands. Macros are also a common way for scammers to sneak malware onto your computer.

Back in the 1990s, scammers frequently used this trick until Microsoft set all its software to automatically block macros. This forced scammers to abandon this technique and find new ways of fooling users. With this new malware, scammers hope today's Excel users have forgotten all about macros.

What if my file is asking me to enable macros? Is this a scam? It can be hard to know when to allow macros in your Microsoft files. Follow these tips to ensure you don't accidentally allow a virus to run on your computer.

Whenever you open an Excel workbook that contains macros, you can verify their source before you enable them. Just look for the digital signature, an electronic stamp of authenticity.

Learn more about macros

Set your macro security level to control what happens when you open a workbook that contains a macro. You can choose to run macros based on whether they are digitally signed by a developer on your list of trusted sources. (To find this setting, go to the Tools menu, Macro submenu. Then, click the “Security Level” tab in the “Security” dialog box).

Watch out for macros in other Microsoft software. This scam involves Excel, but if this technique works, scammers will produce similar tricks using PowerPoint and Word documents.

You can learn more about macros on Microsoft's support website. To find out more about other scams, check out BBB Scam Stopper.

Marjorie Stephens is the communications director for the Better Business Bureau of Northern Indiana. Before you make a purchase, go to the BBB website at or call 423-4433 or toll-free 1-800-552-4631 to check out a business.