Spyware is a type of software that secretly forwards information about a computer user's on-line activities to another individual or company without the user's knowledge or permission.
Earthlink suggests it may infect up to 90% of all internet-connected computers. Typically, says the ISP, it arrives bundled with freeware or shareware, through e-mail or instant message, or by someone with access to a user's computer. Once on a hard drive, spyware begins reporting the next time the user goes on-line. Unlike most software applications, spyware is difficult to detect and can be difficult to remove.
Matt Cobb, EarthLink's vice president of core applications, said:
"While most spyware is adware-related and relatively benign, it's disturbing that over 300,000 of the more serious System Monitors and Trojans were uncovered. This figure represents how real a threat identity theft or system corruption is for users."
The company defines spyware as a collective term for adware, adware cookies, system monitors and Trojan horses.
Adware is any software application in which advertising banners are displayed while the program is running and then sends data back to a third party without permission. Adware cookies are a mechanism that allows a web site or software to record a user's surfing habits without their knowledge or consent.
System monitors are designed to keep track of a consumer's computer activity and can record virtually everything a user does online. Keystroke loggers, a type of system monitor, record each user's keystroke, possibly exposing the user to risk of information and identity theft.
Trojans are applications that appear as harmless programs, but instead facilitate theft of computer data by permitting hackers to gain unrestricted access to computers while Web surfers are online.
To further inform consumers about the dangers of spyware, EarthLink offers a free-of-charge spyware detection program, SpyAudit.