Ransomware is malicious code that encrypts computer files. This makes files unusable until a ransom is paid. Typically, cyber criminals will send out many emails encouraging recipients to click on a link, which then exploits some software vulnerability. Usually, many different victims will be targeted and small amounts demanded from each, often in bitcoins. This is a virtual currency but which has real world values. A recent survey of large companies revealed that over half had experienced an attempted ransomware attack last year. Government advice is not to pay although the ransom may be less expensive than trying to sort out the problem.

Staff training to recognise email threats will reduce the number of ransomware attacks.