New versions of Trojan horses, a form of "malicious software" or "malicious code" that masquerade as a legitimate file, are becoming greater threats to computer users.

Computer attacks will be more severe this year, said Ken Dunham, director of malicious code at iDefense, a Virginia-based intelligence company.

But he said that the motive of attack has changed.

"It's a coordinated, careful attack," Dunham said. "They attempt to steal information and profit. You will see more malicious attacks motivated by money and power. It's just getting worse, not better."

As opposed to computer viruses, however, Trojan horses do not duplicate themselves and are hidden as legitimate programs or attachment to e-mail messages. The Trojan horse would then be able to corrupt a computer in many ways, such as disturbing an infected user's connection to an Internet server or stealing passwords from an infected computer.

Trojan horses have been a problem at the university, said Clifford Rodack, Penn State residence hall network coordinator.

"This is getting so bad that almost every machine we look at is full of spyware," Rodack said in an e-mail message.

Spyware is a type of program that can be used as a Trojan horse and allow a person to infect computers with a virus.

From there, an individual is able to steal passwords and spy on the actions of the infected computer.

One of the latest Trojan threats disguises itself as a Windows XP update. The Trojan.Xombe is sent to many e-mail accounts as junk e-mail, or spam. Computer users are instructed by a valid-looking e-mail message from Microsoft to update their Windows package.

But Microsoft does not send updates to its users.

The Microsoft Web site allows subscribers to update their computer software on a regular basis.

Dunham noted that prior attacks often gave clues, such as spelling errors, that the message was not from the actual company. This is not usually the case anymore.

"[Hackers have] increased their level of sophistication," Dunham said.

Another recent Trojan horse presents itself to Internet users in a spam e-mail message claiming to come from eBay's online PayPal payment service.

If the user downloads the Trojan, it is then able to spread a worm.

"Unless you signed up for a service, don't open the e-mails with an explicit sense of trust. Don't believe everything you see in online form," Dunham said.

He also suggested that computer users install anti-virus software and firewalls, such as the ZoneLabs program.

Sarah Humphries (senior-biochemistry and molecular biology) said computer viruses are an issue on college campuses.

"I don't know how many students update their virus protection on a regular basis or even have it," Humphries said.

In a Penn State Housing e-mail message to students, the university stated that it has activated a firewall, a system that regulates what goes into or out of a computer network from the Internet, as of Jan. 12 for residence hall computer users. Penn State Housing explained the firewall would not allow students to run any type of server, utilize file sharing or peer-to-peer networks, or browse a network neighborhood.

"During the course of the semester, we are constantly cleaning spyware and viruses off computers," Rodack said. "The new firewalls will help students keep from spreading viruses so much. This will help, but better computer hygiene skills are needed to prevent their machines from going down at all."

Robert Owens (junior-biobehavioral health) supported the use of firewalls, and said he takes precautions such as installing anti-virus protection.

"Free firewalls work great," Owens said.

Angi Lee (senior-food science) does not support the use of firewalls.

"It's pretty annoying because I can't receive files" such as pictures, Lee said.

Rodack encouraged students to install the free and powerful Symantec anti-virus system that is licensed by Penn State.

Pop-up ads are one indication that spyware is present on a computer.

Dunham said college campuses have been a target in the past.

"Organized crime has targeted college campuses to steal credit card numbers and other sensitive information. Be careful out there," Dunham said.