Computer Virus Guide

Macro Viruses

When the user double-clicks on an e-mail attachment, most systems are configured to start the application associated with the file type. For example, a .doc file will start in Microsoft Word, an .xls file in Excel, etc.

The trouble is that these applications will also execute any macros within the received file, enabling a virus to infect.

Most e-mail applications can be configured to view a received file using a 'viewer'. Viewers normally do not have macro capabilities. Even if an infected file is examined in such a way, the virus will not infect the environment.

Most users do not need to edit the received attachments, which makes using this strategy throughout the organisation a very effective anti-virus technique.