geeklog- ultimate geek knowledge: Types of Virus Threats and early prevention of them : How to know which virus threats you are exposed to? : Concerning Viruses I

There are a vast number of threats that could affect your computer today.

Worms

This malicious program category largely exploits operating system vulnerabilities to spread itself. The class was named for the way the worms crawl from computer to computer, using networks and e-mail. This feature gives many worms a rather high speed in spreading themselves.

Worms penetrate a computer, search for network addresses of other computers, and send a burst of self-made copies to these addresses. In addition to network addresses, worms often utilize data from e-mail client address books. Some of these malicious programs occasionally create working files on system disks, but they can run without any system resources at all (with the exception of RAM).

Viruses

Programs that infected other programs, adding their own code to them to gain control of the infected files when they are opened. This simple definition explains the fundamental action performed by a virus - infection.

Trojans

Programs that carry out unauthorized actions on computers, such as deleting information on drives, making the system hang, stealing confidential information, etc. This class of malicious program is not a virus in the traditional sense of the word (meaning it does not infect other computers or data). Trojans cannot break into computers on their own and are spread by hackers, who disguise them as regular software. The damage that they incur can exceed that done by traditional virus attacks by several fold.

Recently, the most widespread type of malicious program damaging computer data has been worms. Then follow viruses and Trojans. Some malicious programs combine features of two or even three of these classes.

Adware

Program code included in software, unbeknownst to the user, designed to display advertisements. Adware is usually built into software that is distributed free. The advertisement is situated in the program interface. These programs often also collect personal data on the user and send it back to their developer, change browser settings (start page and search pages, security levels, etc.) and create traffic that the user cannot control. All this can lead to breach of the security policy and to direct financial losses.

Spyware

Software that collects information about a particular user or organization without their knowledge. You might never guess that you have spyware installed on your computer. In general, the goal of spyware is to:

trace user actions on a computer;

gather information on the contents of your hard drive; in such cases, this more often than not involves scanning several directories and the system registry in order to compile a list of the software installed on the computer;

gather information on the quality of the connection, bandwidth, modem speed, etc.

Riskware

Potentially dangeerous applications include software that has not malicious features but could form part of the development environment for malicious programs or could be used by hackers as auxiliary components for malicious programs. This program category includes programs with backdoors and vulnerabilities, as well as some remote administration utilities, keyboard layout togglers, IRC clients, FTP servers, and all-purpose utilities for stopping processes or hiding their operation.

Yet another type of malicious program that goes along with programs like adware, spyware, and riskware is programs that plug into your web browser and redirect traffic. You have most certainly encountered such programs if you have ever opened one web site when you thought you were pulling up another.

Jokes

Software that does not cause a host any direct harm but displays messages that such harm has already been caused or will result under certain conditions. These programs often warn the user of dangers that do not exist, such as messages that pop up about formatting the hard drive (although no formatting actually takes place) or detecting viruses in uninfected files.

Rootkits

Utilities used to conceal malicious activity. They mask malicious programs to keep anti-virus programs from detecting them. Rootkits modify the operating system on the computer and alter its basic functions to hide its own existence and actions that the hacker undertakes on the infected computer.

Other dangerous programs

Programs created to set up DoS attacks on remote servers, hacking into other computers, and programs that are part of the development environment for malicious programs. These programs include hack tools, virus builders, vulnerability scanners, password-cracking programs, and other types of programs for cracking network resources or penetrating a system.

Related Links:

The information presented herein is adapted from Help and Support Section of the Kaspersky Anti-Virus 7.0, details of the notes can be pertained from related links as following: