Malicious Software,

Malware, also known as Malicious Software, is software designed to infiltrate or damage a computer system without the owner's informed consent. The term is a portmanteau of the words malicious and software. 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.

Many normal computer users are however still unfamiliar with the term, and most never use it. Instead, "computer virus" is incorrectly used in common parlance and even in the media to describe all kinds of malware, though not all malware are viruses.

Software is considered malware based on the perceived intent of the creator rather than any particular features. Malware 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, for instance in the legal codes of several American states, including California and West Virginia.[1]

Malware should not be confused with defective software, that is, software which has a legitimate purpose but contains harmful bugs.

Of all computer code released today the majority may be malicious. Preliminary results from Symantec sensors published in 2008 suggested that "the release rate of malicious code and other unwanted programs may be exceeding that of legitimate software applications."[2] According to F-Secure, "As much malware [was] produced in 2007 as in the previous 20 years altogether."[3] Malware's most common pathway from criminals to users is through the Internet, by email and the World Wide Web.[4]