What is the Excel/Laroux virus?

The Excel Macro/Laroux virus consists of two macros: auto_open and check_files.

The auto_open macro executes whenever an infected spreadsheet is opened, followed by the check_files macro that determines the startup path of Excel. If there is no file named PERSONAL.XLS in the startup path, the virus creates it. This file contains a module called "Laroux."

PERSONAL.XLS is the default file name for any macros recorded under Excel. Thus, you might have PERSONAL.XLS on your system even though you are not infected by this virus. The startup path is by default set as \MSOffice\EXCEL\XLSTART, but it can be changed from Excel's Tools/Options/General/Alternate Startup file menu option.

If an infected workbook resides on a write-protected floppy, an error occurs when Excel tries to open it and the virus cannot replicate. Excel Macro/Laroux is not intentionally destructive and contains no payload; it replicates, so most likely will not harm Microsoft Office.