Ransomware exploded onto the public consciousness this year following the devastating WannaCry attack that affected more than 230,000 computers in 150 countries.
The crippling effects on the 47 NHS Trusts hit by the sardonically-named worm led to IT systems being shut down and operations cancelled. Although the attack brought the threat to the forefront of cyber security concerns, it was already recognised to be a major risk by experts around the world.
And now attacks in Ukraine, which was caused by GoldenEye ransomware, according to Bitdefender Labs, is reported to have taken the national bank, state power company and Kiev's largest airport offline.
In early 2016 Kaspersky Lab revealed that it had become the most frequent cyber threat, the same year that Cisco Systems called it the most profitable type of malware attack in history, due to the scale of its impact and the ease by which ransom can be received in cryptocurrency.
The best defence is a combination of thorough end user training, an offline backup solution, and effective cyber-security software. Anti-ransomware tools can add a layer of security to your systems, and most of them are free. We review the best options available.
Read next: How to respond to ransomware threats