Ransomware
Ransomware is a type of malicious software, or malware, that prevents you from accessing your computer files, systems, or networks and demands you pay a ransom for their return. Ransomware attacks can cause costly disruptions to operations and the loss of critical information and data.
You can unknowingly download ransomware onto a computer by opening an email attachment, clicking an ad, following a link, or even visiting a website that's embedded with malware.
Once the code is loaded on a computer, it will lock access to the computer itself or data and files stored there. More menacing versions can encrypt files and folders on local drives, attached drives, and even networked computers.