- Alumni |
- Students |
- Faculty & Staff |
Understanding the Differences between Trojan Horses, Viruses, Worms and Spyware
Viruses, worms, Trojan horses, and spyware all fall in the broad category of “malicious codes” but there are differences among them. For instance, worms and Trojan horses are not viruses. The differences are described below. To best protect your computer from these malicious codes, visit the Computer Security page.
Trojan Horses
Trojan horses are malicious programs that disguise themselves as harmless applications like screen savers. Trojans do not replicate themselves; instead, they rely on users to be spread, frequently through downloading free software. Trojans can capture information about your system such as passwords or user names and allow a hacker to take control of it from a remote location.
Viruses
Viruses are malicious bits of code that are hidden in executable programs, a disk’s boot sector, or in executable macros. When the infected application, file, or disk is run, opened, or accessed, the virus attempts to replicate itself to other machines. Viruses enter your system via e-mail, downloads, infected floppy disks, or (occasionally) hacking.
Worms
Unlike Trojan horses or viruses, a worm replicates itself through network connections to any machine that it can infect and then replicates with those computers to infect other computers. Worms do not require user intervention and often propagate unbeknownst to the user.
Spyware
In general, spyware is any technology that aids in gathering information about a person or organization without his or her knowledge. Spyware is programming that is installed or placed on your computer to secretly gather information about you and relay that information to advertisers, companies, or individuals interested in your internet surfing habits. Spyware can occur as the result of a software virus or installing a new program. Data collecting programs that are installed with the user's knowledge are not, properly speaking, spyware if the user fully understands what data is being collected and with whom it is being shared. Spyware, however, is often installed without the user's consent, such as a sneak-in download, or as the result of clicking some option in a deceptive pop-up window.
