Microsoft® Windows® Security: Essentials

Comparing Malware

Malicious software (malware) is software that is installed on a system without the user’s knowledge or consent. It includes viruses, worms, Trojan horses, spyware, and more.

If a computer is turned on, it’s susceptible to infection from malware. The majority of malware is delivered through the Internet (such as via email), but there are many other delivery mechanisms. For example, an infected USB flash drive may install malware on a system as soon as the flash drive is plugged in.

The primary purpose of malware today is making money. Malware attempts to gather as much data as possible, and then attackers use that data for monetary gain. This is sometimes done by stealing identities, stealing financial data, and clearing out ...