Our Glossary contains many terms that may be used throughout the website in addition to the malware removal guide that we offer. This Glossary will assist you on defining many technical terms used to describe various computer security-related aspects.


A software application in which advertising banners are displayed while the program is running; sometimes, also tracks user information, which makes it also spyware.

Anti-Virus Software

A class of program that searches your disk drives, floppy drives and other removable drives for any known or potential viruses.


A means of access to a computer system that bypasses security mechanisms, installed sometimes by an authorized person, sometimes by an attacker.


A bot (short for “robot”) is a program that operates as an agent for a user or another program or simulates a human activity. On the Internet, the most ubiquitous bots are the programs, also called spiders or crawlers, that access Web sites and gather their content for search engine indexes.

Browser Hijacker

Programming that alters your browser settings so that you are redirected to Web sites you had no intention of visiting.

Buffer Overflow

Type of attack that sends more data than a buffer was intended to hold; surplus data will overflow into adjacent buffers, corrupting or overwriting the valid data held in them or may. Data sent may include malicious code.

Bundled Software

In the software industry bundled software (a.k.a. bundle, bundles, bundling) is software distributed with another product – it might be a piece of software or a piece of hardware. This is the newest and the most used distribution technique for spreading adware, spyware, ransomware etc infections.

Denial of Service (DoS)

An incident in which a user or organization is deprived of the services of a resource they would normally expect to have.

Directory Harvest Attack

An attempt to determine the valid e-mail addresses associated with an e-mail server so that they can be added to a spam mailing list database.

Distributed Denial of Service (DDoS)

Same as DoS but using a big number of infected computers. Very dangerous type of attack, which affects mostly hosting providers or internet service providers.

E-mail Virus

Malicious computer code sent to you as an e-mail note attachment. The best two defenses against e-mail viruses for the individual user are (1) a policy of never opening an e-mail attachment (even from someone you know) unless you have been expecting the attachment and know what it contains, and (2) installing and using anti-virus software to scan any attachment before you open it.

Hybrid Virus

A virus that combines characteristics of more than one type of virus to infect both program files and system sectors. The virus may attack at either level and proceed to infect the other once it has established itself.

Hybrid Virus/Worm

Malicious code that combines characteristics of both those types of malware, typically featuring the virus’ ability to alter program code with the worm’s ability to reside in live memory and to propagate without any action on the part of the user.

IM Worm

Self-replicating malicious code that spreads in instant messaging networks.

In the Wild

Malicious computer code that spreads in the real world as a result of normal day-to-day operations.


Type of spyware program that records the user’s keystrokes invisibly and either transmits them to the attacker on an ongoing basis or saves them to a secret file in the user’s computer to be sent at a later time.


Programming or files developed for the purpose of doing harm. It is an abbreviation of “malicious software” terms.

Macro Virus

Virus that infects a word processing application and causes a sequence of actions to be performed automatically when the application is started or something else triggers it. Macro viruses tend to be surprising but relatively harmless.

Password Cracker

Program used to identify an unknown or forgotten password, often used by a human cracker to obtain unauthorized access.


Quick-repair job for a piece of programming, often as a result of some discovered vulnerability.

Patch Management

Area of systems management that involves acquiring, testing, and installing multiple patches to an administered computer system.


The actual malicious code of the software virus.

Port Scan

Series of messages sent by someone attempting to break into a computer to learn which computer network services, each associated with a “well-known” port number, the computer provides.


An attempt to gain access to a computer and its files through a known or probable weak point in the computer system.


A PUP (Potentially Unwanted Program) is a program that may be unwanted, despite the possibility that users consented to download it. PUPs include spyware, adware, and dialers, and are often downloaded in conjunction with a program that the user wants.


A collection of tools (programs) that enable administrator-level access to a computer or computer network. It allows an attacker to mask intrusion and gain root or privileged access to the computer and, possibly, other machines on the network.


Derogatory term used to describe immature and unskilled — but unfortunately still dangerous — malware creators.

Social Engineering

A non-technical kind of intrusion that relies heavily on human interaction and often involves tricking other people to break normal security procedures.


Unsolicited e-mail on the Internet


Programming that is put in someone’s computer to secretly gather information about the user and relay it to advertisers or other interested parties.


Refers to an event, object or file that evades methodical attempts to find it.

Stealth Virus

A virus that includes mechanisms that enable it to hide from anti-virus programs.

Trojan Horse

A virus in which malicious or harmful code is contained inside apparently harmless programming or data.


A piece of programming code usually disguised as something else that causes some unexpected and usually undesirable event. A virus is often designed so that it is automatically spread to other computer users. Generally, there are three main classes of viruses: file infectors, system or boot infectors, and macro viruses.

Virus Hoax

A false warning about a computer virus. Virus hoaxes are usually forwarded using distribution lists and will typically suggest that the recipient forward the note to other distribution lists. If you get a message about a new virus, you can check it out by going to one of several Web sites that keep up with viruses and virus hoaxes.


Self-replicating virus that does not alter files but resides in active memory and duplicates itself. Worms use parts of an operating system that are automatic and usually invisible to the user. It is common for worms to be noticed only when their uncontrolled replication consumes system resources, slowing or halting other tasks.

Zero Day Vulnerability

A Zero Day Vulnerability is a security hole in a software product, that is unknown to the vendor. The security hole is then exploited by hackers before the vendor becomes aware and releases some fix – update or patch to fix it. This is also called Zero-Day Attack.