Malware is a collective term for various types of malicious and unwanted software. Malware is not the same as a virus. As a rule, malware does not spread like a virus over the local computer network or the internet.
Malware generally has the purpose of causing damage to your computer. Malware disrupts the regular operation of the computer.
Types of malware are computer worms, trojans, adware, and spyware. These types of malware are designed to manipulate the operation of the computer.
Malware manipulates the computer in such a destructive manner that regular operation is hindered, and the computer user is searching for a solution to resolve the problem.
A computer worm can also spread successfully via the internet. An example of a successful computer worm is the LoveLetter (ILOVEYOU) computer worm. The LoveLetter worm pretended by e-mail to be a “iloveyou” letter and had the program icon of Windows Visual Basic scripting, making it very similar to a letter and infected a lot of computers in a short period of time.
Trojans give access to computers for people who want to harm them or gain control to issue the next attack.
More and more adware is also aimed at changing the home page, new tab, and/or search engine of the web browser. In this way, adware developers try to generate web traffic for their website, which in turn generates revenue.
In most cases, adware is bundled together with free software on the internet. Free software is then installed by a Pay Per Install installation program.
Spyware is used to steal personal data from the user’s computer after installation. Think of login details, images, documents, etcetera.
In some cases, spyware is also installed to steal the user’s surfing behavior and resell this information to rogue advertising networks. These ad networks use this information to adapt their sales techniques to the user better. Spyware that sells your data is a category of spyware that is located in a gray area between “normal” spyware and adware.
It is often virtually impossible for computer administrators to decrypt data that has been encrypted by Ransomware. The encryption abused by Ransomware developers is so secure that it often takes years to unlock a single file.
Ransomware is distributed across the internet in many different ways. We know that Ransomware is bundled via free software (just like adware). However, Ransomware is also used in specific attacks that only target a person or company.
An antivirus program can prevent a lot of malware. It does not really matter whether it is a free antivirus program or a paid one. With a paid antivirus program you often get support from the developer of the antivirus software.