Virus classification

Computer threats

An enormous amount of malicious software programs exist, especially for Microsoft Windows operating systems, that endanger your computer or your data in various ways. Depending on the type of behavior they can be classified into a few categories.

It is designed to display unwanted advertising and sometimes slowdown your computer.
Piece of software that bypasses normal authentication procedures, and allows easier access in the future for the attackers.
Browser hijacker
Specialized software to change your home page and search engine used by web browsers for unwanted advertising or information stealing.
Specialized software capable of recording every keystroke you make on your computer, usually for stealing your passwords or other personal information.
Software packages that try to avoid detection by the user by modifying the operating system. Usually they are deployed with backdoors.
A special kind of trojan horse designed to spy on all user actions in all programs. Records keystrokes, passwords, personal information, emails, web surfing activity, and submits harvested information to a malicious user.
Trojan horse
A broad term for malicious programs disguised as something normal or desirable, that attempt to trick the user to willfully install it without realizing its harmful potential.
A computer virus is a self-replicating program that spreads by inserting copies of itself into other executable code or documents and it behaves similarly to a biological virus.
A special variant of computer viruses capable of infecting computers over the internet or local networks. Usually their main purpose is to attack certain web sites, send spam, or to act as a trojan horse.
A catch-all term to refer to any software designed to cause damage to a single computer, server or computer network, whether it’s a virus, spyware, trojan horse… It is a short form for malicious software.