Ransomware attacks show no sign of abating, as people continue to find their computer blocked with fraudulent messages demanding payment to unlock it.
The malicious software, malware, shows a message from the New Zealand police accusing users of breaching copyright laws or viewing explicit content. Users are told they have 72 hours to pay a fine, and regain access, or face criminal charges.
NetSafe cyber security programme manager Chris Hails said 100 ransomware cases have been reported to Netsafe this year, but the actual number is likely to be far higher.
"Lots of people are embarrassed about being accused of this sort of thing, so they go to a family member or friend for help instead."
Ransomware is most commonly spread through phishing emails, said Symantec principal sales engineer Mark Shaw. These are legitimate-looking emails containing fraudulent messages, and malware infected links and attachments.
Other methods included drive-by-downloads, where the computer is infected without the user's knowledge. Users can be surfing the web and click on a malware infected link or advertisement.
"If the software is not updated then these automated tools can look for ways in," said Hails.
Hails said small businesses, especially those with outdated software, were especially vulnerable to attacks.
"If a small business has no IT manager then it's easy for someone to gain backdoor access."
He said the ransom demand can be anywhere up to $4000. As many people were ashamed to admit to this, they paid the fine.
"They're preying on human frailty."
A standard message said users needed to buy an Ukash, eMoney, voucher from a supporting Whitcoulls store. Users then enter the 10-digit Ukash PIN into the screen to unlock their computer.
Hails said reports suggested this did work.
A Whitcoulls spokesperson said these vouchers were terminated "well over a year ago" for an unrelated reason.
Shaw said the data and figures collected showed there were more than one million global ransomware attacks last year.
Although hackers may not be able to access the computer's data during every attack. Shaw said it would be "naive" to assume they were not.
Shaw said this was easier to prevent than cure. He recommended employers educate staff on which sites were and were not acceptable, made sure they had a reputable up-to-date security system and effective back up and recovery systems.
"This is not a passing fad."
The New Zealand police are aware of these messages, but have not received any complaints for 2013.
Ransomware attacks were first reported in Eastern Europe four years ago.
Cyber Security Awareness Week starts today to promote free computer security advice, and information to consumers and small businesses.
Do you feel better off than at this time last year?