What is Malware?

Malware, short for malicious software, is software used or created by hackers to disrupt computer operation, gather sensitive information, or gain access to private computer systems. While it is often software, it can also appear in the form of scripts or code. ’Malware’ is a general term used to refer to a variety of forms of hostile, intrusive, or annoying software.

Malware includes computer viruses, computer worms, Trojan horses, most rootkits, spyware, dishonest adware, and other malicious or unwanted software, including true viruses. Viruses are sometimes confused with worms and Trojan horses, which are technically different. A worm can exploit security vulnerabilities to spread itself automatically to other computers through networks, while a Trojan horse is a program that appears harmless but hides malicious functions. Worms and Trojan horses, like viruses, may harm a computer system’s data or performance. Some viruses and other malware have symptoms noticeable to the computer user, but many are surreptitious or do nothing to call attention to themselves. Some viruses do nothing beyond reproducing themselves.