What is the Difference Between Viruses, Worms, and Trojan Horses?

While we know that computer viruses, worms, and Trojan Horses are all bad news, most of us can’t explain the difference between the three, or we hear people use the terms interchangeably. All three terms are technically different and refer to different types of malicious software that can damage your PC or laptop.

Viruses
Computer viruses attach themselves to files or programs, infecting each computer it comes across as it spreads –often through email attachments. They replicate themselves, and most come attached to an executable file, which means a person has to actually run the program for the virus to become active and spread. Some viruses are merely annoying and slow down your computer, while others can wreak havoc on your system.

Worms
Worms are similar to viruses because they self-replicate but unlike viruses, they don’t have to attach themselves to a program. Instead they use computer networks to send malicious software to other computers, spreading from computer to computer. Extremely dangererous, because they can replicate themselves so successfully and do major damage– even to servers.

Trojan Horses
Trojan Horses are sneaky:  while they appear harmless, they really are programs that hide all sorts of malicious goodies, just like when the Greeks gave a huge wooden horse to their foes, the Trojans. After the horse was within the walls of their city, Greek soldiers came out of the hollow horse belly and they were able to capture Troy. Yikes. In computers, these horses are usually very successful in duping us, because at first glance they seem to be legitimate software.  Once installed however, they can make mildly annoying changes to your computer, or they can go through and delete your files. Trojan Horses do not replicate themselves the way viruses and worms do.

Now that you know the difference between the three types, here’s what you can do to protect yourself:

1. Turn on your firewall.
2. Install and utilize anti-virus software, and be sure to update it as necessary.
3. Utilize an anti-malware program. ChicaPC-Shield™ is a free scan you can run to see if you have any malware currently lurking on your PC.
4. Don’t click on anything you aren’t sure about. If something seems suspicious, chances are it is.
5. Back up your computer, and do it often! Protect yourself in case the worst happens.

–Angela Skinner Mullen