Browser hijackers generate profit and traffic to websites that capture personal computer data or install key loggers, malware or adware to steal sensitive information, such as usernames and passwords.

Methods of infection:

• Normally, these hijackers are installed by hazardous free applications, ad-supporting programs or shareware, which include a variety of browser plug-ins and toolbars. In many instances, removing the host application does not eliminate the bundled-up parasite.
• Many adware and spyware parasites have built-in browser hijackers, which are quietly installed during the host parasite’s installation process. Removing specific adware or spyware doesn't remove the browser hijacker.
• Some regularly-found browser hijackers enter the machine by means of Internet Explorer (IE) ActiveX controls, or by taking advantage of browser vulnerabilities.

A typical parasite can severely complicate a user’s work and decrease productivity. Negative effects can include the following:

• Favorite and most frequently visited sites get blocked.
• Browser safety is minimal.
• Web queries fail to proceed through search engines.
• Necessary data may not be accessed.

Browser hijackers may also attack the system and installed applications. These parasites can trigger browser instability problems, repeated errors and general performance problems.

Preventative tools include vigilance and common sense. For example, never click pop-up ads from an unknown or untrusted website when installing extensions, such as Google Toolbar. If a software application requests approval prior to download, carefully review product terms and conditions to avert blind browser hijacking.

Merijn Bellekom developed the CWShredder hijacker removal tool to combat CoolWebSearch (CWS), one of the first browser hijackers to direct Web user traffic to search engine results with multiple forms of adware. At that time, antivirus, adware and anti-malware programs lacked hijacker removal capabilities.