Malware is any software application which subverts the will of the legitimate owner of a computer, by means of force or subterfuge, with or without personal or monetary gain on the part of the creator.
"Malware" is a portmanteau of "malicious" and "software"
Common forms of malware include:
- Botnet clients, which grant the malware author some degree of control over the compromised operating system and are generally employed in sending spam e-mail and may be rented out to perform DDoS attacks.
- Data exfiltrators, which collect and transmit data about the computer they reside on back to the creator. These are commonly used to target login and account details for financial, social networking, and gaming websites.
- Rogue Utility Applications, which attempt to use scare tactics in order to entice the computer's user to purchase the "full version" of the Rogue Utility.
- Adware, which causes advertisements to appear on the user's desktop, in web pages, or elsewhere.
- Rootkits, which attempt to conceal the presence of both the rootkit and (usually) an accompanying piece of malware from another category from standard system tools and diagnostic utilities.