E-mail attachments from unknown sources are considered to be very dangerous since they have the potential to contain any type of script, virus and/or executable program that can cause severe damage to files and/or disks on the users' computer. In fact, even attachments from trusted sources may contain scripts or macros that the sender unknowingly passes along to the recipient. On downloading an attachment and opening it, a user can trigger a sequence of events that may cause a series of events, often without the user's knowledge.

There are several secure behaviors that users should practice to minimize their risk of infection by viruses through attachments. The first is that users should never open an attachment from an unknown source. The best idea is to delete any attachment, along with the entire e-mail, that comes from unexpected sources. Secondly, if an unexpected attachment is sent from a known address, such as a friend, family member or colleague, users should get in the habit of confirming with the sender that he or she sent the attachment and that the attachment is safe. Remember, some viruses are programmed to proliferate by sending themselves to every address in the victim's address book, so a virus may have been sent from a friend's e-mail without their knowledge. The third practice to adopt is to always scan attachments with an anti-virus program prior to opening it, just to make sure that the attachment is not infected.

This is really annoying. I receive almost everyday such attachments coming from unknown. How can I avoid them?