What is spyware and how to protect myself against it?

Spyware is malicious software that works in the stealth mode on a computer to intercept and log system activity and to rely this information to a third party over the Internet.

Spyware can record the keystrokes you type, messages you send or logins and passwords you use to authenticate yourself at shopping or banking sites. Spying software is often used to conduct online identity theft.

Spyware installs on a computer when a user installs the infected program that they downloaded from the Web. Some spyware programs are being sent in spam messages.

To protect yourself against spyware you must not download programs or open files from unknown sources.