Ransomware has been around for a long time, but it’s only recently that it’s become a major threat to businesses. Ransomware is malware that infects and holds your computer hostage until you pay the attackers in order to regain access. Originally, ransomware was simply an annoyance—a common form of cybercrime that could be easily remedied by restoring files from backups or removing malware. But with modern versions like Locky and Cerber making headlines, this evolving form of cybercrime is now posing serious risks to both businesses and consumers alike. Here’s what we know about how ransomware works—and how it’s evolved over the years: