How Does Ransomware Work?
Ransomware is malware that prevents users from accessing their files by encrypting them with a key controlled by the attacker. Victims are then presented with a screen that requests a payment — usually in the form of cryptocurrency like Bitcoin — to decrypt their files.
Attackers use a variety of methods to get ransomware into systems, including exploiting security holes in operating system and other software programs. Email is one of the most common ways to spread ransomware, with phishing messages and attachments often fooling victims into clicking on malicious links. Other variants of ransomware rely on chat platforms, removable Universal Serial Bus (USB) drives and browser plugins to gain entry into a computer or network.
Once ransomware has access to a computer, it will typically encrypt files with an attacker-controlled key and replace the originals. In many cases, the attacker will only encrypt essential files to ensure the system can still function. But some versions of the malware will also delete backup and shadow copies of infected files to make it more difficult to recover without the decryption key.
Once the attack is complete, victims are told via a message on their computer or on a locked screen (common to encryptors and screen lockers) that they must pay a specified amount within a given timeframe to regain access to their files. Many victims report that paying a ransom doesn’t guarantee the attacker will provide them with the decryption key they need to recover their data. In addition, it may encourage cybercriminals to conduct further attacks as they can see that their tactics are effective.