VULHUB ™

A potential problem exists in the way that Microsoft Windows handles file extensions. Under usual circumstances, when opening an unknown file type, the user is prompted with a dialogue box asking what application should be used to execute the file. This is not the case with Microsoft Office documents when opened in Windows Explorer. If a file is made in an Office application and the extension is renamed to an unknown file type, Windows will still open the file in the corresponding Office program. Reportedly this is because Windows uses header information to determine the file type rather than the file extension itself. Problems could arise if a malicious user were to embed macro viruses in an Office document and then rename the extension to *.vi?. Some antivirus programs will not scan files with the extension of *.vi?. Therefore, viruses contained in such Office documents would go undetected.

A potential problem exists in the way that Microsoft Windows handles file extensions. Under usual circumstances, when opening an unknown file type, the user is prompted with a dialogue box asking what application should be used to execute the file. This is not the case with Microsoft Office documents when opened in Windows Explorer. If a file is made in an Office application and the extension is renamed to an unknown file type, Windows will still open the file in the corresponding Office program. Reportedly this is because Windows uses header information to determine the file type rather than the file extension itself. Problems could arise if a malicious user were to embed macro viruses in an Office document and then rename the extension to *.vi?. Some antivirus programs will not scan files with the extension of *.vi?. Therefore, viruses contained in such Office documents would go undetected.