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Appendices
Appendix C. Malicious Programs and
Methods of Neutralizing Them
With the development of computer technologies and network solutions
malicious programs (malware) of different kinds, meant to strafe
users, become more and more widespread. Their development began
together with computer science and facilities of protection against
them progressed alongside. Nevertheless, there is still no common
classification for all possible threats due to their unpredictable
development character and constant improvement of applicable
technologies.
Malicious programs can be distributed through the Internet, local area
networks, e-mail and portable data mediums. Some of them rely on
the user’s carelessness and lack of experience and can be run in
completely automatic mode. Others are tools controlled by a computer
cracker and they can harm even the most secure systems.
This chapter describes all of the most common and widespread types
of malware, against which products of Doctor Web, Ltd. are aimed.
Classification of malicious programs and other computer
threats
Computer viruses
This type of malicious programs is characterized by the ability to
implement its code into the executable code of other programs. Such
implementation is called infection. In most cases the infected file
becomes a virus carrier itself and the implemented code does not
necessarily match the original. Most viruses are intended to damage or
destroy data on the system. Viruses which infect files of the operating
system (usually executable files and dynamic libraries) and activate
upon launching of the infected file are called file viruses.
Some viruses infect boot records of diskettes and partitions or master
boot records of fixed disks. Such viruses are called boot viruses. They
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