Prestige 662H/HW Series User’s Guide

CHAPTER 17

Anti-Virus Packet Scan

This chapter introduces and shows you how to configure the anti-virus packet scan.

17.1 Overview

A computer virus is a small program designed to corrupt and/or alter the operation of other legitimate programs. A worm is a self-replicating virus that resides in active memory and duplicates itself. The effect of a virus attack varies from doing so little damage that you are unaware your computer is infected to wiping out the entire contents of a hard drive to rendering your computer inoperable.

17.1.1 Types of Computer Viruses

The following table describes some of the common computer viruses.

Table 62 Common Computer Virus Types

TYPE

DESCRIPTION

 

 

File Infector

This is a small program that embeds itself in a legitimate program. A file infector is

 

able to copy and attach itself to other programs that are executed on an infected

 

computer.

Boot Sector Virus

This type of virus infects the area of a hard drive that a computer reads and

 

executes during startup. The virus causes computer crashes and to some extend

 

renders the infected computer inoperable.

Macro Virus

Macros are small programs that are created to perform repetitive actions. Macros

 

run automatically when a file to which they are attached is opened. Macro viruses

 

spread more rapidly than other types of viruses as data files are often shared on a

 

network.

E-mail Virus

E-mail viruses are malicious programs that spread through e-mail. These can

 

infect your computer even if you do not read the e-mail messages.

17.2 Signature-Based Virus Scan

The “signature-based” approach is the most common way to detect the presence of viruses. Signature-based anti-virus scanning consists of two key components: a pattern file that contains the signatures for known viruses and a scanning engine.

Signatures are byte patterns that are unique to a particular virus. These signatures are stored in a pattern file. The scanning engine compares the files with the signatures in the pattern file.

Chapter 17 Anti-Virus Packet Scan

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