Glinx FAQs - Viruses and Trojans

FAQ - Viruses, Trojans and Worms

What is a computer virus?

A virus is a program or piece of code that is loaded onto your computer and runs without your knowledge. Some are simply annoying, while others can be very destructive. Most viruses replicate themselves. All computer viruses are manmade.

What are worms, macro viruses and Trojans?

Some people distinguish between general viruses and worms. The "worm" acquired its name because of the way it gradually infects a system, much like a worm eating it' way through an apple. Most worms will try to infect as many computer files as possible, including free space. Other worms duplicate by attaching themselves to e-mail, or other file transfers.

A macro virus is embedded in a document instead of a program. Documents created in programs like Microsoft Word and Microsoft Excel can be infected with macro viruses.

A Trojan Horse is a destructive program that pretends to be a useful one. Most Internet-acquired viruses are initially dropped by Trojans. The Trojan contains the virus code or program, which then infects your computer. So, although the Trojan itself might not be self-replicating, the virus it contains is. One of the worst types of Trojan horse is a program that claims to get rid of viruses, but instead introduces them onto your computer.

How do you get a virus?

Before the Internet became popular, the most common way to become infected with a virus was by putting an infected disk into your computer, which would infect your system.

With the Internet, there are more common ways to become infected:

WWW or FTP:
When you download an infected file from a page on the World Wide Web, or from an FTP site, and then run that file, your system will become infected as well.

E-mail:
The only way you can get a virus from e-mail is by opening an infected file that was sent as an attachment. E-mail is text only, and is not executed (loaded) like programs are, so there is generally no risk in simply reading an e-mail message.

Unfortunately, programs like Microsoft Outlook have had major security holes exploited by e-mail viruses. MS Outlook tries to be user-friendly by automatically running scripts in e-mail messages. Microsoft has more information on this security problem at http://www.microsoft.com/technet/security/bulletin/ms99-032.asp.

Hoax e-mail messages are constantly going around the Internet, saying that some important and well-known company has issued a warning about reading e-mail, usually identifying it as having a certain subject. These hoaxes play on people’s insecurities and lack of knowledge, because they instruct the recipient to forward the warning message to everyone they know. If he tells two friends, and they tell two friends, and so on, and so on...This is how these fake, virus warning messages are perpetuated.

CIAC Virus Myth and Hoaxes Site – http://ciac.llnl.gov/ciac/CIACHoaxes.html

Created as a public service by the Computer Incident Advisory Capability (CIAC) to educate people about virus myths and hoaxes.

Computer Virus Myths - http://www.kumite.com/myths/

Contains information about the newest hoaxes as well as background on computer viruses and myths, opinions and editorials, and recommended books and Web sites.

Chat:
IRC (Internet Relay Chat) and ICQ (I Seek You) programs have the ability to send and receive files. This is like downloading a file from Web or FTP that is infected. You must run the program before you will become infected.

How can I protect myself from getting a virus?

Consider the source when you download files from the Web or when using FTP. If it is a reputable site like Microsoft or Netscape, then you should be safe. No company wants to ruin its reputation by spreading viruses. However, if you download a program from a site belonging to someone's personal homepage, consider carefully before running the program. While this person may be a genuine good person who wrote a cool program, they may also be a person who wrote a virus and wants to spread it around.

If you receive a file attachment in e-mail or chat, then check to see who it is from. If it is from someone you know, then you will probably be fine...unless that person doesn't take precautions for viruses. If your anti-virus and anti- Trojan software is current, you can run a virus scan. If a virus is not detected after running the scan, then it is probably safe.

Remember, if you don't open or run an infected file, then you can't become infected.

How can I find out if I have a virus or Trojan? How do I get rid of it?

There are many virus checkers and protection programs available, both in shareware trial versions, and in full commercial versions. These can be bought at most computer software retailers, or directly on-line over the Web.

These programs contain a list of viruses (or Trojans), for which they scan your computer. They also contain inoculation procedures, so that if a known virus (or Trojan) is detected, it can be removed.

New viruses are being written all of the time, which is why it is important to keep your anti-virus software current. An anti-virus program that was purchased new 8 months ago is probably useless, because it will not detect any viruses that have been created since the program was written.

Most anti-virus programs now have an "Automatic Update" feature, which allows you to update the program easily. This should be run frequently, such as once a month.

Here are some protection programs that are available. These three, Norton, F-Prot, and McAfee, all scan for known Trojans as well as known viruses.

McAfee Virus Information home page
McAfee Associates specializes in network and security management. This page displays company news and product information, as well as links to virus descriptions, and on-line technical support.

Symantec Anti-virus Research Center
The Symantec Anti-virus Research Center offers a wealth of information on viruses. It begins with a list of hot topics (new viruses and virus products) and also provides links to virus alerts, an information database, references, virus reporting, Macintosh viruses, and Symantec virus product information. Home of the Norton Anti-Virus program.

Data Fellows website
The DataFellows website has information on viruses and virus alerts, and is also home to F-Secure Anti-Virus Toolkit (a group of security programs) and the F-Prot stand-alone virus scanner.

DataFellows also has a free DOS anti-virus program that also checks for Windows viruses. You may download F-Prot from the Datafellows FTP site by clicking here.