Can we protect ourselves from the virus plague?

Network communications represent an easy means for the spread of viruses. Internet users are constantly threatened by the spread of new viruses hidden in appealing objects such as jokes, games, chats, and e-mails ostensibly sent by friends. Although e-mail and www systems represent the main "open doors", floppy and CD disks are still minor "contributors". The damage provoked by infections can be very costly for an organization's time and resources and can become critical when it affects sensitive systems and data. A basic rule in computer security is to make frequent backups to avoid any kind of data destruction or corruption. Various countermeasures can be applied to prevent infections, such as activating an anti-virus SW, or setting filter rules on the e-mail server in order to discard dangerous files present in the message. Another important factor is the awareness of the problem: users must become familiar with both risks and elementary defense techniques (i.e. do not open executable files, disable automated macro activation, etc.). In this work we present data statistics of virus attacks revealed by an anti-virus SW activated on our e-mail server and discuss results in terms of virus types and temporal distribution. The work is organized into two parts. The first part includes a brief overview of virus types (parasitic, macro