A Computer Spyware can install on your computer without your knowledge. These programs can change your computer’s configuration or collect advertising data and personal information like internet surfing habits, user logins, and bank or credit account information. Spyware can track Internet search habits and can also redirect your web browser to a different websites than you intend to go to.
Spyware is mostly classified into four types: adware, system monitors, tracking cookies, and trojans; examples of other notorious types include digital rights management capabilities that “phone home”, keyloggers, rootkits, and web beacons.
Spyware does not necessarily spread in the same way as a virus or worm because infected systems generally do not attempt to transmit or copy the software to other computers. Instead, spyware installs itself on a system by deceiving the user or by exploiting software vulnerabilities.