Malware is content which can cause damage and disable the functioning of information systems

Malware is any software run on a computer without actual consent of the user which has some sort of an undesirable effect (damage to the system programs or information, spreads to other computers, steals data—particularly sensitive data such as passwords and credit card numbers, enables unauthorised remote access to the computer, shows undesirable or malicious ads, causes massive sending of undesirable e-mails—spam, participates in attacks on other computer on the network...).

Depending on the way in which a malware program spreads, it can be categorised as a computer virus, worm or Trojan horse. Depending on how it operates and for what purpose, we can also categorise malware as, for example, spyware, adware, crimeware, scareware, keyloggers, rootkits and ransomware.


Ransomware is the term used for a set of malware programs which block the user from using the computer and can lead to significant consequences. Once a computer is infected, ransomware can encrypt files or block their usage by displaying a certain message on the home screen which cannot be removed. The user whose computer is infected is requested to provide a ransom in exchange for further normal operation of the computer and return of their data. Recently, there have been more and more cases in which the malware program encrypts the user data and in exchange for its decryption requests payment of a certain amount of money, most commonly in Bitcoin (crypto ransomware).

How to protect oneself from malware:
  • Make sure that your computer and any security software (antivirus software) that you use is up to date.
  • Regularly upgrade your most used applications, such as Microsoft Office, Adobe Reader, Mozilla Firefox, etc.
  • Pay special attention to the websites you use to obtain information or where you browse certain types of content, especially if you are accessing them for the first time
  • Turn on a firewall
  • Make frequent and reliable backups of important data and store these separately from the computer which you are backing up
  • Do not open links or e-mail attachments from unknown or suspicious sources

Even if you follow all security guidelines for information security, keep in mind that malicious users can always find defects in the IT system and will try to infect your computer with malware.