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What Are Computer Worms, Viruses & Trojans?

Computer viruses, trojan horses and worms are malicious programs with the sole purpose of giving you a headache, causing grief and stealing personal information. The malware makes your computer less reliable and sometimes jeopardizes your identity. Some malware deletes data from your computer, some use e-mail to spread worms and others completely wipe your hard drive.

While most people know the importance of protecting themselves and their system from malware by using antivirus software, many people don’t understand what exactly computer viruses, trojans and worms are. So, in an effort to help you understand what this malware is and how you can protect yourself from it, we’re going back to the basics of trojans, worms and viruses.

computer security

Trojan Horse

I’m not talking about giant wooden horses that are made with the intent of hiding warriors who will jump out after they’ve breached the enemy’s city walls. (That’s the other Trojan horse.) When I talk about trojan horses, I’m talking about computer programs that claim to do something, but instead damage your system when you execute (open) it. Trojans can come in any form – video games, antivirus programs, photos – and are set up to initiate ‘battle’ once you’ve double clicked them. Trojans can’t replicate themselves automatically, they can only harm your system if you execute them. You can’t get mad saying you got a trojan horse from someone because the only way you can get a trojan is if you open up a file that is infected.

Trojans can:

  • Install spyware onto your computer which will take you to unwanted websites.
  • Change your desktop or add silly active desktop icons.
  • Do malicious functions like rebooting your computer or erasing files
  • Create backdoors to your computer which will allow hackers to gain control of your system without your permission. The hacker can then see your e-mails, access password protected accounts , record your keystrokes, and get any personal information about you from your computer.

Recommended: Bitdefender Internet Security

Computer Worm

I once had a co-worker tell me her work computer was being de-frogged (she meant defragged). My mind instantly imagined a bunch of little frogs hopping out of her tower. So, in case you are new to the technology world, when I say worms I don’t mean the kind of worms you fish with or find lying on the sidewalk after a rain storm.

Computer worms are small pieces of software that will use your computer network and securities to replicate itself. Worms will steal your personal information for someone whose motives are less than noble. You should be as cautious about letting worms into your computer as you would be to let them into your food because once they get in, they are really hard to get rid of.

In some ways worms are more deadly than viruses because they don’t need to lodge themselves into programs to replicate – worms can replicate independently through your system. Once in your system, worms will look scan your network for other machines that may have similar security holes. If the worm finds one, it will copy itself into the new computer and start the process all over again.

Worms can:

  • Spread via infected e-mail messages as any form of attachment or a link to an infected website.
  • Scan the Internet for vulnerable machines and then try to connect with the machines to gain full access.
  • Copy itself into a shared folder on a local machine under a file name that seems harmless. The worm then waits, ready for download until the file is opened.

Recommended: Trend Micro Internet Security

Computer Virus

Computer viruses have basically been around since the beginning of time … computer time that is. Before the Internet came around and before computers were all networked together, viruses spread much more slowly (usually with floppy disks) than they do now. Now programmers are trained to limit the possibilities of virus infections, but viruses are still prevalent.  Viruses can attach themselves to just about any type of file and then spread to other computers via infected files. Malicious programmers are constantly creating new viruses, some of which are harmless and some of which are devastating – which is why up-to-date antivirus software is absolutely critical.

Viruses can:

  • Corrupt or delete information of your computer
  • Use your e-mail to spread itself to other computers via e-mail attachments or instant messaging messages
  • Wipe your hard drive
  • Spread through downloads on the Internet. Some viruses are hidden in software or other files and programs you may download, which is why it’s important to only download from sites that you trust.

Malware is kind of an Information Age marvel. Malware shows us just how vulnerable we really are – if properly engineered, malware can have absolutely devastating effects, disrupt productivity and cause billions of dollars of damages. On the other hand, malware shows us just how interconnected and sophisticated humans have become recently.

Recommended: Kaspersky Internet Security

To protect your system from viruses, worms and trojans, you can:

  • Install antivirus and antispyware software to your system. This software can detect and remove the malware. For the best protection, make sure to keep your software current.
  • Don’t download files or programs from people you don’t know or from sites that aren’t 100% trusted.
  • Use caution when you open e-mail attachments, even from people you know.
  • Don’t receive files from unknown people while chatting.
  • Set firewalls on for your computer because they can open ports for incoming data on your system. Firewalls will help keep hackers out of your system.
  • Be careful when you are engaging in P2P (peer-to-peer) file sharing. Don’t download files with extensions like .exe, .scr, .lnk, .bat, .vbs, .dll, .bin, and .cmd.
  • Make sure to configure your instant messaging application so that it doesn’t open automatically when you start your computer.
  • Stay aware of current virus and malware news.

Author Bio: Kate Schneiders is a technogeek and self-proclaimed ‘word nerd.’ A journalist at heart, Kate enjoys researching and writing about the best antivirus software, security and credit card processors.

{ 2 comments… add one }
  • [email protected]

    February 20, 2011, 8:58 pm

    Nice article friend. Personally i think that viruses, trojans malware and the like are simply just another form of business, driven by the actual software companies who create the “solution” to our virus problems. I mean, think about it, If your name was Norton (just an example) and you needed to boost company revenues to keep up with inflation and make the chosen few fatter, what would be your next move? Just a thought…

  • [email protected]

    February 18, 2011, 2:04 pm

    very good explanation kate, you have done well 🙂


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