A new wave of ransomware is attempting to extort money from Kiwis in exchange for returning access to their computer files.

Netsafe has received seven reports over the last week of a new type of ransomware virus locking up the computers of both home users and small businesses in New Zealand.

Ransomware encrypts the files on your computer using a powerful algorithm and demands payment, usually by a certain date.

The new version is displaying as Anti Child Porn Spam Protection 2.0 and in some cases uses the New Zealand Police logo.

How the latest version of Cryptolocker displays on screens.
How the latest version of Cryptolocker displays on screens.

Netsafe’s digital project manager Chris Hails said the average amount demanded was half a bitcoin, which is currently worth about $NZ350. However, one of the recent cases came with a demand for $3000.

“It can affect anyone, from a 74-year-old woman like we had last week, all the way up to a business with 500 staff,” Mr Hails said.

While Netsafe didn’t encourage paying money to those behind the ransomware, it acknowledged it was the only option in some cases and some people have had success decrypting their files by paying the demand.

Mr Hails said Kiwis needed to take preventative steps to keep computer systems “patched”, by updating operating systems and applications, and by using a modern browser for surfing. Users should also ensure data back-ups were working. Anti-virus software would also help prevent common forms of ransomware.

An attack usually occurs after the user clicks on an email attachment or visits an affected website.

“It’s pretty nasty. With a normal virus you can keep using your computer, it may slow it down but you can clean it up with virus protection,” Mr Hails said.

If an attack does occur, Mr Hails recommended taking the computer to a technician, who could try and restore the system, clean up and wipe the hardware, and reinstall Windows and the data affected.

Android and Mac devices can also be attacked, but so far in New Zealand affected Macs have only got the less serious browser-locking version and Androids haven’t been hit.