Spyware or Virus?

Category: Anti-Virus , Security

I had an anti virus program by McAfee but uninstalled because it was bogging my computer down. I now have anti spyware software, so do I still need to get an anti virus program? What is the difference between viruses and spyware? To me they seem very similar...

spyware and computer viruses

Viruses and Spyware - Are They Different?

A computer virus is a malicious self-replicating computer program that spreads by inserting copies of itself into other programs or documents, similar to the way a real virus operates. When the infected program or document is opened, the destructive action (payload) is repeated, resulting in the infection, destruction or deletion of other files. Sometimes the infected programs continue to function normally, albeit with the side effects of the virus; in other cases the original program is crippled or destroyed.

Technically, viruses are just one of several types of malicious software (malware), which differ mainly in the way they are transmitted. In common usage, the term virus is often used to refer to other sorts of malware such as worms, trojan horses and spyware. Following are definitions of each of those terms.

What is a Computer Worm?

A worm is a malicious computer program that is self-contained and does not need help from another program to propagate itself. Typically, they exploit the host computer's email transmission capabilities to send copies of themselves to everyone found in the email address book. Some even look in the cache of recently visited web pages and extract other email addresses to target.

The main difference between a computer virus and a worm is that a virus requires some action from a user to propagate, while worms replicate without any intervention. Another difference between the two is that worms generally do not harm the target computer, but can harm the surrounding network by clogging it with copies of itself. In some cases, a worm can spread so quickly within a large organization that the network either slows to a crawl or collapses under the strain.

What is a Trojan Horse?

A Trojan horse is a malicious program that is disguised as or embedded within legitimate software. The term is derived from the classical myth of the Trojan Horse. Such a program may look useful or interesting, but is actually harmful when executed. Examples may include web browser toolbars, games and file sharing programs. A Trojan horse cannot operate or spread on it's own, so it replies on a social engineering approach (tricking the user into taking some action) rather than flaws in a computer's security.

What is Spyware?

spyware and computer viruses Spyware is a type of malicious software designed to intercept or take partial control of a computer's operation without the informed consent of the user. While the term taken literally suggests software that surreptitiously monitors the user, it has come to refer more broadly to software that subverts the computer's operation for the benefit of a third party. In simpler terms, spyware is a type of program that watches what users do with their computer and then sends that information over the internet. Some spyware tracks what types of websites a user visits and send this information to an advertisement agency. More malicious versions try to intercept passwords or credit card numbers. Others may launch annoying popup advertisements.

Who Writes Viruses?

Remember that kid in high school, the one with the uncool sneakers, the no-name jeans, or the tape on his glasses? You should have been nicer, because now he's in charge of the computer system where you work. He can see all your files, your emails, and he knows what websites you visit. The creator of a computer virus may have revenge, corporate sabotage, or political upheaval in mind; he or she may be naively experimenting with software techniques; or the writer may be looking for notoriety. But the typical virus writer may not be the malcontented miscreant in our stereotypes. Some research shows that most live apparently normal lives, but share an undeveloped sense of ethics. Hmmm, sorta like serial killers...

In March of 1999, the Melissa virus began spreading through the Internet via a Word document with an infected macro. The virus exploited Outlook Express to email itself as an attachment to the first 50 people in the user's email address book. The virus-laden emails were sent with a subject line of "Important message from [name]" and text reading "Here is that document you asked for" in the message body, which caused it to spread very quickly. Over a million computers were infected, causing an estimated $80 million in damage. David Smith, the author of Melissa, first posted the infected Word document to the alt.sex newsgroup on Usenet, claiming that it contained passwords allowing free access to adult websites. Smith was caught within a few days, and plead guilty to a federal charge of spreading a computer virus. He paid a $5000 fine and served 20 months in prison.

What's In A Name?

But was Melissa really a virus? It did infect other files, but it also propagated on it's own. And it used social engineering tactics to appear as if it was a useful document from a known person. Some might call Melissa a hybrid virus/worm/trojan. And that might underscore the point that it really doesn't matter what you call a malicious software program. I tend to support the populist trend of calling them all viruses, even though I am trained as a computer scientist.

What does matter is that your computer has the proper protection. You do need both anti-virus and anti-spyware protection on your computer. Some security software suites roll it all into one program, but for now the best protection I've found is a combination of several programs. Read the article Should I Buy Anti-Spyware or Anti-Virus Software? to learn how I protect my own computers.

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Most recent comments on "Spyware or Virus?"

Posted by:

Howie M
17 Sep 2006

You mentioned that you "...tend to support the populist trend of calling them all viruses...". Given that there important differences, wouldn't it be better to call it "malware", which is all encompassing, which "virus" is not? (Of course if you define malware as anything that wreaks havoc on your computer, then I guess Windows, Norton and McAfee would have to be included :))

EDITOR'S NOTE: Yes, malware is a better term to cover all the bases. But terms like "virus" and "hacker" are so ingrained in our culture that it's like spitting into the wind to try and correct it.

Posted by:

23 Nov 2006

Hey I was just wondering if certain websites are more harmful to your computer than others. For example I like going to the WWE website, but I computer person said it was very harmful to your computer right up next to adult videos. Is this really true, and if so is there a way to make the website safe??

EDITOR'S NOTE: Some websites do attempt to trick users into downloading spyware or viruses. But the WWE site doesn't appear to have any such issues. You should always read the privacy policy at a site before offering up ANY personal info. And of course use a good anti-virus and anti-spyware scanner.

Posted by:

Scott Nicoll
12 Feb 2007

I have the "Norton Internt Security", I had "Spyware Doctor" also, but the subscription ran out. Is Norton sufficient?

EDITOR'S NOTE: Norton is a bloated resource hog, not sure if it has anti-spy component. Here is my recommendation:


Posted by:

07 Jul 2007

hey, ever since yesterday my high speed internet had dropped from downloading at 300kb/secs to 2kb/secs! Is this spyware? what should i do?

EDITOR'S NOTE: I'd ask your ISP if there is a signal problem. And of course do a complete virus/spyware scan.

Posted by:

14 Aug 2007

Hello, I recently got a "restart virus," I believe, that would keep on restarting my computer (I posted in the computer restarting section). I used System Restore to send my computer back to August 6th, and then, it was working fine. I did two virus scans and found no viruses after. I then tried to install a free trial of PC-Cillin, and tried to scan with Trend Micro House Call. The House Call would not work, and PC-Cillin seemed to mess up my computer! I tried deleting PC-Cillin totally off of my computer, but every time I right click on my desktop, it tried to use a Windows Installer that tries to install to here: C:\Program Files\Xfire\downloads\metadata\TrendMicroPCCsmall\

It also says that it can't put it to there, and that something doesn't exist. I don't know how to get rid of it trying to install. Can you help me any? (And thanks on the on the other topic.)

EDITOR'S NOTE: Did you delete PC-Cillin with Control Panel's Add/Remove Programs, or manually?

Posted by:

15 Aug 2007

Well, after it started to freeze up my computer and make it act strangely, I had to use the power button to shut it off and turn it back on a few times, and the PC-Cillin desktop icons were gone, but it still had parts of it on it. So, I could not find it in Add/Remove Programs, and did a Search to find files, and I manually sent any files I could that delt with Trend Micro and PC-Cillin to the Recycle Bin for deletion.

Posted by:

22 Nov 2007

Hello Ryan I'm haveing the same problem with Trend Micro trying to re-install itself all the time. I tried to manualy delete everything but I couldn't find a way to delete tmdshell.dll.

Let me know if you found a way to resolve fully delete trend micro. I'm almost at the point of scraping everything and load the original system recovery cds.

Please if any one could help, I would appreciate it.

Posted by:

19 Dec 2007

I had Trend Micro on my computer recently and I wanted to deleted. Well I did the add/remove programs like normal on all my programs I take off. It still shows that I have it on there. So I went into my program files and found out that the folder for Trend Micro was still there. So I tried manually deleteing and it said that I couldn't delete the tmdshell.dll file??? How do I delete the DLL file please.

EDITOR'S NOTE: Some programs are not completely gone until after a reboot...

Posted by:

Jay Miller
25 Dec 2007

Every time I try to go to a Website using Yahoo, the word {Continue} shows up in the upper left hand corner of the page after a slight hesitation. Then it changes me to another site that I did not type in. What can I do to prevent this? Also every time I try to Restore to an earlier time I am informed that it failed and no changes were made to my computer.. Any advice will be appreciated.

EDITOR'S NOTE: Sounds like a spyware hijack. I would try the free Windows Defender for a spyware scan/remove sweep.

Posted by:

Sean Creagh
26 Dec 2007

Hey Bob, i've been messin around with computers for years now without any real training. I reckon i've got a fairly good grasp of how to remove malware and the likes from a computer expecially my own. I've been lookin around your site while cleaning out my computer manually and using the internet to try check out files I wasnt sure about. One thing has got me a little confused though. My computer has recently started scrolling randomly up and down. While online, while reading texts documents, and even during games sometimes even locking scrolled down or up. I dont really know whats causing it and I can't seem to find any programs that could be the cause. Any ideas as to what it is exactly? Dust in the mouse?

EDITOR'S NOTE: Yes, my first guess would be a dirty or defective mouse.

Posted by:

Durga charan ojha
01 Aug 2008

Hi Bob,

I got a lot information regarding virus and their activity. It will help others to have a good knowledge of virus and they can keep their computer free from it.

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