What's the difference between a 'Trojan Horse' a 'Worm' and a 'Virus'?

Read the article that everyone's commenting on.
Subscribe to the RSS Feed for comments on this article.

Maybe it is possible to be a little clearer on the definitions.

1. Virus: the key feature of the computer coded virus is that, like the organically-coded virus, it can replicate itself from within an infected system, and spread itself to another recipient. The mechanism of spread, be it Internet via a webpage or email, or via a floppy disc or CD, is immaterial. A virus may carry a "payload" of code which it deposits on the infected host - the payload os often a worm or trojan.

2. Trojan: with its name originating from the similarity to the Trojan Horse of Greek mythology, the Trojan is computer code which you inadvertantly allow to enter your computer, past your usual defences. Like the original Trojan Horse, once entry has been granted, any kind of harm may be done to the host, but perhaps the most common purpose of many trojans is to listen for and respond to messages sent from remote hosts, opening access to your PC from the Internet at large, causing a major potential hazard to the integrity ans security of your system.

3. Worm: a computer worm is code that navigates (snakes ?) within an infected network and often damages the system by changing configurations, or by altering or removing files. Worms do not usually self-replicate, but need to be carried to a new network in order to infect it.

4. Phishing: this is the only verb in the list of terms. It is a technique used to dupe computer users into revealing critical financial of security information about themselves, commonly by imitating a legitimate finalcial or other service provider.

Kenneth Spencer

Hi I've been reading about anti-Trojan programs and would like to know:
- are trojan horse programs sufficiently different from viruses and worms that they need a specialised anti-trojan program (for example TDS-3)to detect and remove them - or will an anti-virus program do a thorough job of detection and removal?
- if there is a material differenc, what aspect of Trojans makes them so difficult to detect?

Thanks

The good news is that anti-virus programs, or anti-virus programs coupled with anti-spyware programs, try to cover all of these threats. The bad news is that they can all be difficult to detect.

hey i found ur article very usefull. But what i m actually looking for is what is the difference between the cell phone viruses n computer viruses. I m doing a seminar on cell-phone viruses so would be very thankfull to you if u would provide me with some usefull information.

Thanks You,
Bhumika.

In concept they're the same thing, just written for different propagation techniques, and different operating systems, making use of different vulnerabilities.

my antivirus software norton, states that it can not remove my trojan. what should i use to do so. at the present, i am looking at spyware doctor. is it worth it or should i just swipe my computer

I would try one, or more, other anti-virus programs: http://ask-leo.com/recommendation_antivirus_software.html

its a good article but it wud be better if you wud have given the difference between all the three in the table format.

is there any other cure to trojan except reinstalling the operating system??if so,plz reply.

My son and I use Avast protection on our home computers. Since May he has had a problem with his computer and the issue is the following aspimgr.exe

aspimgr.exe has slowed his computer and deleted his System Restore Points.

Is there any help for him, or do you have any suggestion for him to repair. He has discovered that an Error window with the following message:

The instruction at "0x00919d04" referenced memory at "0x000ab000" the memory could not be "read"

This problem started around the end of May and we discovered tonight if he closes the error it will lock his computer up. To night we discovered that if he does not close the error it seems to work.

It also gives a warning that the virus protection is out of date.

Help Please,

Thank you,

Robert Grahn

This note was written for Andy Grahn

To post a comment on "What's the difference between a 'Trojan Horse' a 'Worm' and a 'Virus'?", please return to that article's main page.