Company PCs swamped with spyware

The average company PC contain 20 pieces of spyware including virulent programs such as system monitors and Trojan horses, according to a study published on Wednesday.

The study was carried out by security company Webroot Software, which carried out a spyware audit on 10,000 PCs in 4,100 companies.

The majority of items found were relatively harmless, such as adware -- software that displays ads and may send data back to a third party. But 5 percent of PCs had system monitors, which track a computer user's online activity, and 5.5 percent had Trojans.

Trojans can be used to install a back door on a PC, allowing an attacker to access the computer to launch spam or denial-of-service attacks. They are often referred to as spyware because of their ability to stealthily run in the background of a computer without being detected.

Richard Stiennon, a vice-president at Webroot, said spyware can lead to the theft of sensitive company information.

"The enterprise offers a bounty exponentially larger than what the everyday consumer's PC might surrender to a spyware program," said Stiennon in a statement. "Everything from customer information to payroll details to product specs and source code are all potential spyware targets. And beyond the potential theft of sensitive information, more benign forms of spyware, like adware, lead to increased bandwidth consumption and decreased employee productivity."

Previous Webroot spyware audits, have found high levels of spyware on consumer PCs.