Ways of Infection
Spyware parasites differ from regular viruses. They do not spread by themselves and usually must be installed as any other software with or without the user’s consent. Some rare pests are able to exploit system security vulnerabilities and act similarly to worms. There are three major ways undesirable spyware program can get into the system.
1. Many spyware vendors deceive the user by presenting a particular spyware program as a useful tool, for example, a powerful web search service, fast download manager or reliable Internet accelerator. Users download and install such programs. However, practically all of them appear to be either completely useless or ineffective. Although in most cases users can uninstall such programs, spyware components stay in the system and remain fully functional.
2. Lots of free, ad-supported or shareware products are bundled with small add-ons needed by the host program to work properly. These add-ons actually are third-party spyware parasites. Uninstalling the host application not always removes bundled spyware.
3. Most widely spread spyware programs get into the system using Internet Explorer ActiveX controls or exploiting certain web browser vulnerabilities. Their vendors run insecure web sites filled with malicious code or distribute unsafe advertising pop-ups. Whenever the user visits such a site or clicks on such a pop-up, harmful scripts instantly install spyware. The user cannot notice anything suspicious, as parasites do not display any setup wizards, dialogs or warnings.
It is known that some spyware can also be dropped by specific viruses, trojans or worms.
Spyware affects mostly computers running Microsoft Windows operating system.
Credit : http://www.2-spyware.com/spyware-removal
