XL2000: How to Reduce the Chances of Macro Virus Infection

This article explains how you can reduce the risk of infecting Microsoft Excel -- including your worksheets, templates, and add-ins -- with macro viruses.

To reduce the chances of contracting a macro virus infection, use one or more of the following methods.

NOTE: Use of these methods does not provide a 100-percent guarantee that you will not contract a macro virus.

Method 1: Install Antivirus Software

For a long-term solution to macro viruses, install antivirus software that is specifically designed to detect macro viruses.

NOTE: After you install an antivirus software program, you must keep it updated to ensure that new macro viruses are detected and removed. For more information about updating your antivirus software program, please contact your antivirus software vendor.

Method 2: Increase the Security Level

Microsoft Excel offers the following levels of security to reduce the chances that a macro virus will infect your worksheets, templates, or add-ins.

Security Level	Description
High	You can run only macros that have been digitally signed and that you confirm are from a trusted source. Before trusting a source, you should confirm that the source is responsible and uses a virus scanner before signing macros. Unsigned macros are automatically disabled, and Excel opens the worksheet without any warning.
Medium	Excel displays a warning whenever it encounters a macro from a source that is not on your list of trusted sources. You can choose whether to enable or disable the macros when you open the worksheet. If the worksheet might contain a virus, you should choose to disable macros.
Low	If you are sure that all the documents and add-ins that you open are safe, you can select this option -- it turns off macro virus protection in Excel. At this security level, macros are always enabled when you open worksheets.

To change the security level in Excel, follow these steps:

1. On the Tools menu, point to Macro and then click Security.
2. On the Security Level tab, select the security level that you want, and then click OK.

For more information about security levels, click Microsoft Excel Help on the Help menu, type security level in the Office Assistant or the Answer Wizard, and then click Search to view the topics returned.


For additional information about "best practices" for avoiding macro virus infection in Microsoft Word, click the article number below to view the article in the Microsoft Knowledge Base:

Method 3: Lock the Project

To lock your Excel project with a password and reduce the possibility of unauthorized access by a macro virus, follow these steps:

1. On the Tools menu, point to Macro, and then click Visual Basic Editor.
2. In the Project Explorer, select ThisWorkbook.
   
   NOTE: If the Project Explorer does not appear, click Project Explorer on the View menu.
3. On the Tools menu, click VBAProject Properties.
4. On the Protection tab, click to select the Lock project for viewing check box.
5. Type a password in the Password box.
6. Type the same password in the Confirm password box.
7. Click OK.
8. On the File menu, click Close and return to Microsoft Excel.

For more information about locking your VBA project, in the Visual Basic Editor, click Microsoft Visual Basic Help on the Help menu, type protection tab in the Office Assistant or the Answer Wizard, and then click Search to view the topic.
For information about how to contact your antivirus software provider, view the following hardware and software third-party vendor contact information: http://support.microsoft.com/gp/vendors/en-us