Malware, short for malicious software, is software used 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. In all countries it is a serious criminal offence to create and distribute malware, but it continues to be produced for various reasons, such as demonstrating a capability or making money.
Malware includes computer viruses, ransomware, worms, trojan horses, rootkits, keyloggers, dialers, spyware, adware, malicious BHOs, rogue security software and other malicious programs; the majority of active malware threats are usually worms or trojans rather than viruses. In law, malware is sometimes known as a computer contaminant, as in the legal codes of several U.S. states. Malware is different from defective software, which is a legitimate software 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 in the form of a useful or attractive program which has the harmful malware embedded in it along with additional tracking software that gathers marketing statistics.