Spyware is a type of malware that’s hard to detect. It collects information about your surfing habits, browsing history, or personal information (such as credit card numbers), and often uses the Internet to pass this information along to third parties without you knowing. Keyloggers are a type of spyware that monitors your keystrokes
Spyware is often bundled with other software or downloads on file-sharing sites (e.g., sites where you download free music or movies), or is installed when you open an email attachment. Because of the secretive nature of spyware, most people are not aware when spyware is on a computer that’s unprotected by anti-spyware.