Malware

Malware (malicious software) may be considered any software designed to infiltrate or damage a computer system without the owner's informed consent. The expression is a general term used by computer professionals to mean a variety of forms of hostile, intrusive, or annoying software or program code.

Software is considered malware based on the perceived intent of the creator rather than any particular features. It includes computer viruses, worms, trojan horses, most rootkits, spyware, dishonest adware, and other malicious and unwanted software. In law, malware is sometimes known as a Computer Contaminant.

Some malicious programs contain routines to defend against removal: not merely to hide themselves, but to repel attempts to remove them. For example, the malware starts a number of processes which monitor one another and restarts any process which is killed off by the operator.