Malware, short for malicious (or malevolent) software, is software used or created to disrupt computer operation, gather sensitive information, or gain access to private computer systems. It can appear in the form of code, scripts, active content, and other software. 'Malware' is a general term used to refer to a variety of forms of hostile or intrusive software.
Malware includes computer viruses, worms, trojan horses, spyware, adware, and other malicious programs. In law, malware is sometimes known as a computer contaminant, as in the legal codes of several U.S. states. Malware is not the same as defective software, which is software that has a legitimate purpose but contains harmful bugs that were not corrected before release. However, some malware is disguised as genuine software, and may come from an official company website. An example of this is software used for harmless purposes that is packed with additional tracking software that gathers marketing statistics.
Malware has caused the rise in use of protective software types such as anti virus, anti-malware, and firewalls. Each of these are commonly used by personal users and corporate networks in order to stop the unauthorized access by other computer users, as well as the automated spread of malicious scripts and software.