How do you get a virus

Lock out viruses and trojans

Computer viruses are defined as certain programs that usually infiltrate standard programs and related files and thus multiply. The process is similar to an infection, so the name was borrowed from medicine. The variety of computer viruses makes an exact classification difficult.


File or link viruses

File or link viruses are classic viruses that copy themselves into computer programs and that can spread further each time it is accessed. The infected programs usually become larger because the code of the computer virus is added.


Boot sector or system viruses

Boot sector or system viruses copy themselves into the boot sector or into the partition table and are loaded at every start (before the operating system). You can nestle on any non-write-protected data carrier (in particular USB sticks, etc.) without this being noticed in the data (unchanged scope).



worms are not considered real computer viruses because their function is different from them. They spread independently on the internet. The goal: worms multiply endlessly to consume memory resources. This reduces the performance of the infected computer. Particularly harmful worms combine the properties of file viruses or carry a Trojan horse with them.


Macro viruses

Macro viruses hide in Word or Excel documents. Basically, useful macros automate work processes. Virus-infected documents, on the other hand, contain a so-called damage routine, which can range from simple jokes to the deletion of files.


Trojan horses

Trojan horses are often malicious programs hidden in harmless, useful programs. They are often used to install additional malicious programs on the infected system, which run independently on the computer. Unnoticed by the user, this malware spies out sensitive data stored on the computer, such as passwords, access and credit card numbers, and transmits them. Other malware is used for unnoticed remote control of the computer and makes the computer part of a so-called botnet.



Hoaxes are bad jokes and are used on the Internet, for example, to give false warnings about malicious viruses: For example, users are asked to delete certain (important) files in order to prevent viruses. The message is usually supplemented with the advice to forward the warning email to friends and acquaintances.


Resident Viruses

Resident Viruses nest in the main memory of the PC and infect data carriers from there.


Stealth viruses

Stealth viruses (Stealth computer viruses) and polymorphic viruses evade combat by recognizing antivirus programs and creating a non-infected state during their activity (invisibility) or by constantly changing their shape (polymorphic, i.e. diverse computer viruses that modify their code). This makes the search for such viruses difficult.


Script viruses

Script viruses can hide in HTML codes and be distributed over the Internet. Viruses of this kind can also be hidden in e-mails if they use HTML format - not only in the e-mail attachment, but also in the e-mail itself.