Malware Terminology

The Information Technology world has a definite jargon of its own, which can be confusing to both the end users and (sometimes) to the IT people themselves. One of our biggest problems these days is Malware (mal meaning “bad”) infections on our users’ computers. In the interests of making the problem a little clearer, here is a basic (if not necessarily complete) dictionary of terms, in plain English.

Adware: Advertising-supported software. This is software that automatically plays, downloads or displays advertisements to a computer. A classic example would be a “helper toolbar” that causes advertising pop-ups on your screen.

Backdoor: Some spyware can install a credential and password that make unauthorized and unexpected entry into a computer possible by an outside user, who can then plant more malware and/or harvest available data.

Bot: A piece of software designed to grant an outside user complete control of your computer at will. A computer affected by bots is called a zombie, and “armies” of like-infected machines can be used to launch simultaneous attacks on other systems, or send out spam email messages.

Browser Hijacker: Code that replaces search pages, home pages or error pages with its own, allowing further browsing to be redirected to wherever it wants you to go (as opposed to where you wanted to go).

Rootkit: Code designed to gain root-access to your computer and manipulate it into allowing viruses or spyware to install and operate, while hiding from anti-virus scanners by appearing to be a part of the operating system.

Spyware: Differing from viruses in that they are not out to wreck your system, but to gain from it – controlling functions or accessing data for financial gain. Spyware might include keystroke loggers, backdoors, or browser hijackers, among other things.

Trojan: A disguise for malicious software, which may be brought into your computer as something apparently safe, but which can drop one or more harmful programs once inside. For example, an image file might contain code that operates only when the image is viewed, which installs backdoors, bots or viruses at that time, but which is otherwise inert.

Virus: A self-replicating program, intended to cause damage in computers. Pretty much pure vandalism, there is generally no gain for the perpetrators…

Worm: A program that looks for holes in your computer’s security, to get itself inside your computer where it can drop its payload (viruses or spyware). It is not, itself, either a virus or spyware, but may be thought of as something like a trojan. It scans IP addresses, opportunistically looking for entry points to exploit.