KAPERSKY ANTI-VIRUS 5.5 - FOR MICROSOFT EXCHANGE SERVER 2000-2003, Руководство администратора, Страница: 6 / 143

CHAPTER 1. INTRODUCTION
The main source of viruses today is the global Internet. Most cases of the virus
infection happen through the use of e-mail. The facts that almost every computer
has e-mail client applications installed and that malicious programs are able to
take a full advantage of software address book in order to find new victims are
favorable factors for the distribution of malware. Without even suspecting it, the
user of an infected computer is sending infected e-mail messages to his or her
contacts, who, in turn, send new waves of infected messages and so on. It is not
uncommon when infected files, due to someone's negligence, enter commercial
mailing lists of large companies. In this case, the virus will affect not just five, but
hundreds or even thousands recipients of such mailings who then will send
infected files to dozens thousands of their contacts.
Apart from the threat of virus or malware infection, there is a problem of
unsolicited e-mail messages and misuse of the internet resources. Not being a
direct threat by itself, unsolicited e-mail messages (SPAM) cause the loss of
working time and inflict serious financial losses.
Additionally, it is to be noted that the newest malicious programs use the so-
called spamming technologies for efficient mass distribution and the methods of
social psychology to make the user open the message, etc. Therefore, SPAM
filtering is important not only for convenience, but also in order to protect your
computer against some new types of viruses.
It is now acknowledged that for some companies information has become a more
important asset than its physical property or cash. At the same time, in order to
gain profit through the use of the information, it has to be available to the
company's employees, clients and partners. This raises the issue of data security
and, as its important element, the issue of protection of the corporate mail
servers against the external threats, preventing virus outbreaks within the
corporate networks and filtering out the unsolicited correspondence.
1.1. Computer viruses and malicious
software
As the number of computer users grows and the exchange of information via the
Internet and email increases in volume, there is an increased threat of computer
virus infection and data corruption or capture by malicious computer programs or
malware.