How Does Spyware Download Onto a Computer?

Spyware is a vague term loosely referring to hidden software packages that monitor a computer's Internet usage and send usage data to commercial websites. Spyware significantly interferes with computer networks due to the bandwidth and other network resources they consume. Some prefer to use the term "adware" to distinguish less intrusive advertising systems from those designed to be more invasive. This page uses the term "spyware" generically, to mean either spyware or adware systems.

Spyware software can download onto a computer in two ways:

• Bundled applications:
  Some types of spyware software are contained inside the install packages of other Internet software downloads. The most common form of bundling occurs with P2P software applications. P2P downloads files for installing Kazaa, for example, contains additional software packages like Cydoor inside the same file.

  Spyware software can also be installed on a computer through download of:

  • some less-reputable Internet Explorer browser toolbars
  • some so-called "agent" or "personal assistant" software like Gator, BonziBuddy and Comet Cursor
  • some packages promoted to be "anti spyware" systems that in fact contain spyware software

  Each of these types of Internet downloads can result in anywhere from one to more than 10 different types of spyware software also being downloaded. Installing the primary application automatically installs the spyware applications, usually without the users knowledge. Conversely, uninstalling an application will often not uninstall the spyware software.

  What to do: To avoid receiving this type of spyware, carefully research online the functionality of a new software application before installing it.

• Triggered download:
  Other forms of spyware software downloads occur simply by visiting certain web pages in Internet Explorer. These pages contain script code that automatically triggers a spyware download as soon as the page is opened. Depending on the browser's version, security settings, and security patches applied, the user may or may not be prompted to accept/reject the spyware download.

What to do : To avoid receiving this type of spyware, either:

• use the most up-to-date versions of both Microsoft Windows and Internet Explorer
• use a web browser other than Internet Explorer
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