Voluntary download

The spyware component lies hidden within an otherwise apparently useful program. Often, the containing program is made available for download free of charge, so as to encourage wide uptake of the spyware component.

Containing programs take all forms:

• Browser components
• P2P/MP3 software
• Vice websites often require a user to install files to view certain picture types, run movies, or run gambling programs.
• Price comparisons/shopper helper programs

Intrinsic browser security holes

While your browser's default Internet security levels may be set to prompt you when a website wants to download files to your computer, it's possible for you in some cases to lower these protections in order to view certain websites. This is not generally recommended and can lead to security holes that can be exploited by nefarious websites.

Human weakness

• Consider the origin of the software for download and the credibility of the site.
• Fake anti-spyware: Don't just use anything that you found through a search engine. You want a name brand that you've read about.
• Pop-ups appear claiming corrective powers for whatever ails your machine. Clicking on the pop-up downloads the spyware.

Fake anti-spyware

Pop-up ads appear claiming corrective powers for whatever ails your machine. Clicking on the pop-up downloads the spyware.

Malicious installation

Most criminal spyware cases involve someone from the same institution installing spyware directly onto the victim's PC.