What’s The Difference Between Viruses, Trojans, Worms And Other Malware?

What’s The Difference Between Viruses, Trojans, Worms And Other Malware?

Lifehacker’s tech-savvy readers are the first people on speed-dial when it’s time to heal an infected PC, but how much do you really know about viruses, spyware, scareware, trojans and worms? Here’s a helpful guide to understanding all the different types of malware.

The point of today’s lesson, of course, is to help you teach your friends and family more about the different types of malware and debunk a few of the common myths about viruses. Who knows, maybe you’ll learn a thing or two as well.

What is Malware?

The word Malware is short for malicious software, and is a general term used to describe all of the viruses, worms, spyware and pretty much anything that is specifically designed to cause harm to your PC or steal your information.

Viruses Wreak Havoc On Your Files

computer virusmalwareImage by Joffley

Most viruses attach themselves to executable files, but some can target a master boot record, autorun scripts, MS Office macros, or even in some cases, arbitrary files. Many of these viruses, like CIH, are designed to render your PC completely inoperable, while others simply delete or corrupt your files — the general point is that a virus is designed to cause havoc and break stuff.

You can protect yourself from viruses by making certain your antivirus application is always updated with the latest definitions and avoiding suspicious looking files coming through email or otherwise. Pay special attention to the filename — if the file is supposed to be an MP3, and the name ends in .mp3.exe, you’re dealing with a virus.

Spyware Steals Your Information

Since spyware is primarily meant to make money at your expense, it doesn’t usually kill your PC — in fact, many people have spyware running without even realising it, but generally those that have one spyware application installed also have a dozen more. Once you’ve got that many pieces of software spying on you, your PC is going to become slow.

What many people don’t realise about spyware is that not every antivirus software is designed to catch spyware. You should check with the vendor to make sure the application you are using to protect you from malware is actually checking for spyware as well. If you come across a PC that is already heavily infected, run a combination of MalwareBytes and SuperAntiSpyware to clean it thoroughly.

Scareware Holds Your PC for Ransom

If you manage to come across a PC infected with one of these, your best bet is to Google the name of the virus and find specific instructions on how to remove it, but the steps are usually the same — run a combination of MalwareBytes, SuperAntiSpyware and maybe ComboFix if you need to.

For more on scareware, including a full walk-through of how a PC actually gets infected in the first place, check out the guide I wrote on removing Internet Security 2010 and other fake antivirus malware.

Trojan Horses Install a Backdoor

Image by otzberg

Once your PC has been infected with the trojan, it can be used for any number of nefarious purposes, like a denial of service (DoS) attack against a website, a proxy server for concealing attacks or even worse — for sending out buckets of spam. Protection against trojans works the same way as viruses — make sure that your antivirus application is up to date, don’t open suspicious attachments, and think long and hard before you try and use a downloaded crack for Photoshop — that’s one of malware authors’ favourite spots to hide a trojan.

Worms Infect Through the Network

Image by me and the sysop

Some of the most famous worms include the ILOVEYOU worm, transmitted as an email attachment, which cost businesses upwards of 5.5 billion dollars in damage. The Code Red worm defaced 359,000 websites, SQL Slammer slowed down the entire internet for a brief period of time, and the Blaster worm would force your PC to reboot repeatedly.

Because worms often exploit a network vulnerability, they are the one type of malware that can be partially prevented by making sure your firewall is enabled and locked down — you’ll still need an updated antivirus software, of course.

Glad to finally put a name to the annoyingly threatening scareware? Does it irritate you when somebody calls spyware a virus? Be sure to send this article to them, and share your malware war stories in the comments.


    • spam and scams that come through the portal are a dangerous and serious threat to australia’s way of life, and its secretly Google that is behind these scams and spams but it has nothing to do with the fact Google turned down Conroy.

      I vote that we get an Anti-Portal Police force set up so that we don’t have to worry about these spams and scams.

    • You know it constantly boggles me why they just don’t appoint a younger minister who is more in touch with the technology. The only theory I can come up with is that he has been given the portfolio as a pat on the back for a past favour, or as some kind of pity-job. But surely they could’ve given him something less important? I’m guessing they view that portfolio as unimportant or at least innocuous anyway, which says something about the current generation of politicians.

  • I didn’t read the article, but the title poses a very good question..

    After all we already know that spam and scams come through the portal..

  • when i first started work in support, one of the staff was reporting a slow computer immediately after reading an email. I chucked my tools on a USB and plugged it in to do some scans. Nothing was found with super anti spyware so I just did some quick optimising of the computer so the staff member could get back to work. A few minutes later my boss needed something copied from the server his laptop. I chucked the same usb drive into the server and the server instantly said DCOM ERROR SHUTTING DOWN IN 30 SECONDS. IT manager spent the next 30 hours fixing it. damn rookies

Log in to comment on this story!