Spyware is a general term used to describe certain behaviors such as advertising, collecting personal information, or changing the configuration of your computer, generally without obtaining your consent.
displays advertisements (called adware) or software that track personal or sensitive information.
This does not mean that any software that provides advertisements or tracks your online activities is bad. For example, you can sign up for a free music service, but you "pay" for this service by agreeing to receive targeted advertising. If you understand the terms and accept them, you may have decided that it is a fair compromise. You can also agree to have the company track your online activities to determine which ads to display.
Other types of spyware modify your computer, which can be annoying and slow down your computer. Programs may change the homepage or search page of your web browser, or add additional components to your browser that you do not need or want. These programs also make it very difficult for you to change your settings to the way you initially have them.
The key in any case is whether you (or someone who uses your computer) understand what the software will do and have agreed to install the software on your computer.
There are a number of ways that spyware or other unwanted software can be installed on your computer. A common trick is to secretly install the software when installing other software like a music or video file sharing program.
Any software that secretly collects user information via the user's Internet connection without his or her knowledge, usually for advertising purposes. Spyware applications are generally grouped together as hidden components of free or shared downloadable programs on the Internet; However, it should be noted that the majority of shareware and freeware applications are not provided with SpyWare. Once installed, the spyware monitors the activity of users on the Internet and transmits this information in the background to someone else. Spyware can also collect information about e-mail addresses and even passwords and credit card numbers
Besides the issues of ethics and confidentiality, SpyWare steals the user by using the resources memory of the computer and consuming bandwidth at the base of the house of the spy via the user's Internet connection. Because SpyWare uses memory and system resources, applications running in the background can cause system crashes or general system instability.
Because SpyWare exists as an independent executable program, it can scan files on the hard drive. , snoop other applications, such as chat or word processing programs, install other Spyware programs, read cookies, change the default home page on the web browser, send back this information regularly to the SpyWare author who will use it for advertising purposes or to sell the information to another party.
Licensing agreements accompanying software downloads sometimes warn the user that a SpyWare program will be installed with the requested software, but license agreements may not always be read completely because Notice of a Spyware installation is often phrased in obtuse and hard-to-read legal warnings.
SpyWare common programs illustrate the variety of behaviors found in these attacks. Note that, as with computer viruses, researchers give names to Spyware programs that can not be used by their creators. Programs can be grouped into "families", not based on a shared program code, but based on common behaviors or "following the money" of apparent financial or commercial links. For example, a number of SpyWare programs distributed by Claria are collectively known as "Gator". Likewise, programs that are frequently installed together can be described as part of the same SpyWare package, even if they operate separately.
o CoolWebSearch, a group of programs, takes advantage of vulnerabilities in Internet Explorer. The package directs traffic to advertisements on websites, including coolwebsearch.com. It displays pop-up windows, rewrites the search engine results and modifies the hosts file of the infected computer to redirect DNS lookups to those sites.
o Internet Optimizer, also known as DyFuCa, redirects Internet Explorer error pages to advertising. When users follow a broken link or enter a wrong URL, they see an ad page. However, because password-protected Web sites (HTTP Basic authentication) use the same mechanism as HTTP errors, the Internet Optimizer prevents the user from accessing password-protected sites.
o Zango (formerly 180 Solutions) advertisers on the websites that users visit. It also modifies HTTP requests for affiliate related ads from a website, so that the ads generate unrealized profits for the 180 Solutions company. HuntBar, aka WinTools or Adware, WebSearch was installed by an ActiveX drive-in download on affiliated websites, or by advertisements displayed by other SpyWare programs. -An example of how SpyWare can install more SpyWare. These programs add toolbars to IE, track aggregate browsing behavior, redirect affiliate referrals, and display advertisements.
oZlob Trojan or simply Zlob, is downloaded to your computer via the ActiveX codec and reports information to Control Server. Some information may correspond to the history of your searches, the websites you visited and even the keystrokes.