Malware, short for malicious (or malevolent) software, is software used or created by attackers 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. 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.