Ransomware
Imagine using your computer and suddenly receiving a message saying your files have been "kidnapped" and that you must pay to get back what is yours.
This is what malware known as "ransomware" does. It has been around for many years, but used to be a bigger problem in Eastern European countries, especially Russia. Increasingly, however, cases are being reported in the United States and now in Brazil as well. Unlike banking password stealers (the most common type of virus in Brazil), this malware is very visible once it infects a computer, since it locks the screen with the "ransom" demand.
There is no better way to describe ransomware than as "digital kidnappers". They are trojans that break into the computer and block access to documents, programs, applications and games, literally "freezing" the user.
The first programs with this behavior were quite simple, and antivirus software could not only remove the malware but also recover the supposedly "kidnapped" files. Before that, the scam was even more indirect: the "ransom" was paid through a fake antivirus program, created by the criminals themselves, that would supposedly "clean" the computer of a virus. Now, however, the fraud is blunt, and recovering the files is very difficult.
When one of these viruses reaches a computer, it encrypts the files and displays a message demanding payment. If the amount is not transferred within a deadline set by the attackers, the "ransom" rises considerably. To receive the money, the kidnappers use the virtual currency Bitcoin, which can be done anonymously.