Ransomware is a growing problem. It's estimated to have affected tens of thousands of Americans in 2016, and according to the FBI, is on track to make nearly $US1 billion ($1.4 billion) a year for the criminals behind it.
At its heart, ransomware is digital extortion. It begins when criminals use subterfuge to get malicious software on to a victim's computer, often through emails that contain software or links to the malware. The ransomware then infects the computer, encrypting files or locking down the entire system.
When the victim attempts to use the machine, a message pops up informing him or her that files or the computer have been hijacked. The target can only regain access by paying a ransom – typically paid in difficult-to-trace digital currencies such as Bitcoin.
Ransomware has become more prevalent, in part due to the rise of what's known as "ransomware-as-a-service". Beginning in 2015, cybercriminals set up ransomware platforms that performed all the necessary functions for the crime, says a recent McAfee Labs report. They rent out this network to bad guys who don't have the technical expertise to do it on their own, getting paid a commission on every successful ransom.
The FBI doesn't support paying ransom in response to a ransomware attack, as there's no guarantee that the criminals will unlock the files and it can encourage criminals to attack others.
However, many individuals and companies do pay up because it's often the only way they can get access to crucial files that are not available via backup. In that case, the criminals often helpfully provide tutorials on how to use digital currencies, even going so far as setting up help desks for their victims to aid them in paying their ransom.