A Yankee Group report in the US found holes in security software had overtaken Windows-related security problems by the end of 2004. Through to May 2005 it found 77 flaws impacting antivirus and other security products. A survey by Bigfoot Interactive discovered 55 percent of on-line users had been infected with spyware and 82 percent believed it posed a threat to their online privacy.

Phishing, which tries to hook people into scams to disclose personal information, is becoming a major threat. For example in New Zealand we’ve seen bogus notifications allegedly from major banks requesting users update secure information because of some problem. This is something the banks would never do, and those duped into following through are likely to find funds illegally withdrawn from their accounts.

A recent report from Symantec, the company behind Norton security products, warns phishing attacks increased from 2.99 million messages a day in the last half of 2004 to 5.7 million in the first half of 2005. Its Brightmail antispam service claims one in every 125 email messages it scanned was a phishing attempt to access confidential information.

Geoff Cossey, director of Chillisoft, says the sheer volume of malware has gone through the roof recently; 18 months ago there were about 100 new examples a day, now there are more than 3000 unique threats.

Some writers create a ‘zombie army’ to hijack people’s computer resources. These may arrive on an email or be picked up through a web browser vulnerability, creating a ‘sleeper agent’ awaiting instructions. Their task may be to log keystrokes looking for passwords, launch a denial of service (DoS) attack on other computers using your bandwidth, or send out spam via a mini mail server downloaded to your machine.

Then there are those annoying pop-up screens warning your PC has been infected with spyware: ‘please click here for removal’. However clicking may actually install the spyware. If the message is not from your own antivirus software, ignore it. And don’t use the button in the middle that says ‘close’ because the whole screen might be live. Instead click the red cross in the right corner to shut it down.

Cossey who represents NOD32, from European-based Eset Software, says 99 percent of people taking the right precautions will not get infected, but a surprising number of users don’t have good antivirus software or fail to keep it up to date.

And he suggests traditional signature-based detection is too slow to capture, fix and disperse antidotes for many of the threats on the internet today. The first iteration may only be active in the wild for three hours, the time it takes for antivirus companies to come up with a fix. In the meantime it’s downloaded an updated version. "There are often cycles of 20-30 of these things in a period of a few days which makes users extremely vulnerable." NOD32 uses heuristics or ‘predictive guessing’ to identify potential viruses, and catch any unacceptable activity on your PC.

There’s no question. Every computer user needs good antivirus protection, and where possibly to update all the operating system and browser patches notified by Microsoft. A firewall on your internet connection is helpful and you should regularly scan your hard disk and ensure your antivirus software is up to date. Typically antivirus software costs between $60-$70 a year.