Info and Service :: Viruses and other malware

Adware

Adware is software that presents banner ads or in pop-up windows through a bar that appears on a computer screen. Those advertising spots usually can't be removed and are consequently always visible. The connection data allow many conclusions on the usage behavior and are problematic in terms of data security.

Backdoors

A backdoor can gain access to a computer by going around the computer access security mechanisms.

A program that is being executed in the background generally enables the attacker almost unlimited rights. User's personal data can be spied with the backdoor's help, but are mainly used to install further computer viruses or worms on the relevant system.

Boot viruses

The boot or master boot sector of hard drives is mainly infected by boot sector viruses. They overwrite important information necessary for the system execution. One of the awkward consequences: the computer system cannot be loaded any moreà

Exploit

An exploit (security gap) is a computer program or script that takes advantage of a bug, glitch or vulnerability leading to privilege escalation or denial of service on a computer system. A form of an exploit for example are attacks from the Internet with the help of manipulated data packages. Programs can be infiltrated in order to obtain higher access.

Hoaxes

The users have obtained virus alerts from the Internet for a few years and alerts against viruses in other networks that are supposed to spread via email. These alerts are spread per email with the request that they should be sent to the highest possible number of colleagues and to other users, in order to warn everyone against the "danger".

Macro viruses

Macro viruses are small programs that are written in the macro language of an application (e.g. WordBasic under WinWord 6.0) and that can normally only spread within documents of this application. Because of this, they are also called document viruses. In order to be active, they need that the corresponding applications are activated and that one of the infected macros has been executed. Unlike "normal" viruses, macro viruses do consequently not attack executable files but they do attack the documents of the corresponding host-application.

Polymorph viruses

Polymorph viruses are the real masters of disguise. They change their own programming codes - and are therefore very hard to detect.

Program viruses

A computer virus is a program that is capable to attach itself to other programs after being executed and cause an infection. Viruses multiply themselves unlike logic bombs and Trojans. In contrast to a worm, a virus always requires a program as host, where the virus deposits his virulent code. The program execution of the host itself is not changed as a rule.

Script viruses and worms

Such viruses are extremely easy to program and they can spread - if the required technology is on hand - within a few hours via email round the globe.

Script viruses and worms use a script language such as Javascript, VBScript etc. to infiltrate in other new scripts or to spread by activation of operating system functions. This frequently happens via email or through the exchange of files (documents).

A worm is a program that multiplies itself but that does not infect the host. Worms can consequently not form part of other program sequences. Worms are often the only possibility to infiltrate any kind of damaging programs on systems with restrictive security measures.

Spyware

Spyware are so called spy programs that intercept or take partial control of a computer's operation without the user's informed consent. Spyware is designed to exploit infected computers for commercial gain. Typical tactics furthering this goal include delivery of unsolicited pop-up advertisements. AntiVir PersonalEdition Classic is able to detect this kind of software with the category "ADSPY" or "adware-spyware".

Trojan horses (short Trojans)

Trojans are pretty common nowadays. We are talking about programs that pretend to have a particular function, but that show their real image after execution and carry out a different function that, in most cases, is destructive. Trojan horses cannot multiply themselves, which differentiates them from viruses and worms. Most of them have an interesting name (SEX.EXE or STARTME.EXE) with the intention to induce the user to start the Trojan. Immediately after execution they become active and can, for example, format the hard drive. A dropper is a special form of Trojan that 'drops' viruses, i.e. embeds viruses on the computer system.