What is a ransomware?
It is a malware (malicious software) that stops you from accessing your data, either by locking you out from your system or encrypting your files. Then it will instruct you to pay the ransom money in Bitcoin, essentially holding your data hostage.
How can you avoid it?
Most of these spread via attached documents in emails or a website link. First, always be cautious when you receive an unexpected email with a link inside or with an attachment, especially when it is coming from an unknown sender. Second, you should also have a working antivirus and firewall. Third, always have backup of your important documents and photos. Make sure your backup media is not always attached, because the ransomware can spread to connected drives and network locations.
What to do when infected by a ransomware?
It can happen when you don’t have an antivirus or it’s not updated or it’s turned off. Perhaps the ransomware is so new that your security software doesn’t know about it. You can’t open your files, your desktop wallpaper might be changed and the same text file will be in every folder with the instructions. You will immediately notice it, so act quick. Never pay the criminals. There is a small chance that it is an older variant that can be decrypted. Disconnect your computer from the network by pulling the network cable out and disabling Wi-Fi, but don’t shut down or restart your PC. From another device search the internet for the encrypted file’s extension, the text in the instructions and the characteristics of it. If you are lucky, you might find a free tool for decryption.
If unlucky, you must reinstall your system and restore your files from backup.