What's on your PC? Spyware, Trojans and diallers

Users are increasingly losing ownership of their PCs with a growing amount of spyware and malicious applications finding their way on to computers in homes and the workplace. Worse still, the infections may go largely undetected.

The issue of spyware has been a major concern so far during 2005 but figures released by Computer Associates show Trojans, diallers, keyloggers and hacker tools also exist on users' PCs in worrying numbers.

Sam Curry, vice president of product management for CA eTrust, told silicon.com: "In all my time I have never seen an increase in the level of a particular threat like we have seen with spyware."

According to CA's findings the average user has 33 traces of adware and four traces of spyware on their machine – all of which may be capable of relaying sensitive information about the user to a remote third party.

The findings show how much damage users could unwittingly be doing to their machines and themselves or their businesses if they aren't aware of the risks. Less tech-savvy home users are likely to be most at risk.

The findings all relate to what was discovered on users' machines the first time they ran a scan for pests and spyware.

"Most systems have around 80 or 90 pieces of potentially malicious code on them within a short time of first connecting to the internet," said Curry.

The rest of those 80 or 90 items are made up of a mix of threats from Trojans and diallers to more benign unwelcome guests.

'Below the radar' applications which covertly drop onto users' machines are also used for increasing the effectiveness of future attacks. CA found an average of five traces of spam tools per machine, three firewall killers and traces of nine miscellaneous cracking tools.

One in three users had a keylogger detected on their machine – an application which is able to record key strokes and thus can detect passwords or other sensitive data. Hijacking applications are also very common.

The average user has at least two homepage hijackers – applications which are often the first to betray the presence of spyware as users notice their homepage changes. Other hijacking tools, such as search hijackers (three of which exist on the average user's PC) will redirect users searching for sites while others will install tool bars or redirect users while they are navigating from one page to another.

Applications such as the notorious CoolWebSearch tool bar - described by Curry as "one of the worst" - and search hijacker commonly take over a user's web session redirecting them to pages they do not request.

"The question end users should be asking, is do they have control of their PC at all times and do they have control of their relationship with the internet?"

Curry believes the answer is a resounding 'no', with more and more systems polluted with spyware and Trojans. Some of it is an irritant but some can aid in identity theft.

Speaking to silicon.com, Steve Purdham, CEO of SurfControl, said the increase in the levels of spyware and Trojans can largely be attributed to spammers 'raising their game'.

"Malicious phishing scams, spyware, Trojans and viruses are all playing a far greater role in the tactics of the spammers now whereas previously it was porn and adverts for Viagra," he said.