Installation

• Browser hijackers are installed with freeware programs, which are mentioned in the user's agreement prior to installation, according to SearchSecurity.com. They are also installed after downloading an infected shared file or a file via email. They can also automatically download by visiting a infected website or opening an email message.
  
  

Computer Changes

• Malware causes browser redirects by changing the external code found in a person's Internet Explorer settings. It may utilize security holes in Internet Explorer to change the browser's configuration. It can also change the operating system's registry, making it impossible to prevent the homepage from redirecting to an unwanted website. Manually changing the homepage back to the desired page won't work because the malware overwrites the change.
  
  

IP Redirecting

• These programs can also change the operating system's Hosts file, a file the computer uses to connect to websites by calling the website's associated Internet protocol (IP) address. When activated, these programs force the Internet to direct Web addresses to specific IP addresses, which redirects to an unwanted website. For example, typing in the Web address for a banking website can cause the browser to redirect to a website connected to a different IP address, such as a sponsored search website.
  
  

Other Symptoms

• Aside from redirecting browsers to unwanted websites, browser hijackers also prevent access to websites that can eliminate them, such as anti-spyware websites. They can also disable anti-virus and anti-spyware programs. Hijackers can also change the Internet browser's favorites to contain links to unwanted content, such as porn websites. They may modify the home page to automatically redirect to an unwanted website whenever the Internet browser is opened.