So what exactly is a trojan horse? A giant wooden horse made to fill with warriors who are set to jump out once they have breached the walls of an enemies city! No, not that kind of trojan horse.

A trojan horse is simply a computer program that claims to do one thing, but instead does damage when you execute it. These programs can come in any form. It could be a video game, an anti virus program, or even just a photo. They are set up to initiate once you have double clicked them. Trojans can only cause harm if you have executed them. They have no way to replicate themselves automatically.

Some people will exclaim that they have gotten a trojan horse from someone! But the reality is that if you have a trojan on your computer, it is because you have opened a file that included the trojan.

What Can A Trojan Horse Do?

A trojan can do anything from allowing a hacker to control every aspect of your computer. They can move your mouse before your eyes, or open your rom right in front of you as if you had done it yourself. They can also completely erase your hard drive, or implant more malicious information onto your computer. If you computer contains sensitive materials, a trojan will be your worst nightmare as anything saved to your hard drive will become available to the hacker who is using the trojan horse.

The best way to avoid a trojan horse is the same as avoiding a virus. Never open anything that hasn’t been virus scanned first. But it is important to also remember that not all trojans can be found through a virus scanner. Be sure to download a trojan cleaner and occasionally run it on your computer to be sure of the safety of your files and programs.

Odd as it mat sound, the computer virus is something specifically related to the information age. On one side of it the viruses can show us how vulnerable we are, as a properly generated and utilized virus can have devastating effects on the computer they are on. On the flip side of this they can also show us how intelligent and interconnected human beings have become.

Strange as it may sound, the computer virus is something of an Information Age marvel. On one hand, viruses show us how vulnerable we are — a properly engineered virus can have a devastating effect, disrupting productivity and doing billions of dollars in damages. On the other hand, they show us how sophisticated and interconnected human beings have become. So how does a computer virus work?

What is Computer Virus

A virus is a tiny piece of software that can piggyback itself into real programs. For example, a virus may attach itself to a spreadsheet program such a excel. Each time that spreadsheet is opened, the virus begins to run. It can also have the chance to reproduce itself by attaching itself to other programs.

One of the best way to avoid allowing a virus onto your computer is to make sure you run a virus program scanner on each and every item you download, before you open it. Once you have executed a program, its way too late.

Unfortunately for any computer user viruses and Spyware are a common problem. The worst part is that most people are not aware of some things that may install Spyware or other malicious items onto their computers. Most people wrongly assume that they have to download something or open themselves up to a vulnerability manually. This is not always true.

How Do I Keep Getting Spyware?

Actually, one of the main ways that hackers have found is the easiest to use to get PC users to execute their malicious software is through emails. All of those inspirational or chain emails can be the biggest source of problems for some users who do not even frequent sites that may contain Spyware or viruses.
All of those nice inspirational emails can have malicious coding embedded that may cause security vulnerabilities within your computer. Clicking links that you are unsure of inside emails is also a great way to install Spyware on your system.

For new users this may be the biggest problems. Most people who regularly use computers for personal or business related activities are aware of the dangers of the internet and the possibility of getting Spyware of viruses. However, most think that in order to get them, you have to execute a program. This is entirely untrue.

Delete Those Emails Before You Open Them!

Whatever the title and whomever it has come from does not matter. Always keep in mind that others may not know the dangers of simple emails or links as well. The best way to deal with emails from unfamiliar sources or emails that contain inspirational or chain letter type messages is to delete them as soon as possible. Do not open them ever!

Are you afraid of ghosts? If yes, then chances are that you’ll be afraid of Linux viruses too, because there is an inherent similarity between them. Neither of them exists. In that sense, this article is rather similar to a ghost story – it is about something that sounds sinister enough to make you afraid, yet does not really exist.

Well, that isn’t completely and absolutely true. There is a famous Linux virus called Bliss, which was discovered in 1997. you want to know why it is so famous? Is it because it’s a particularly damaging, destructive, hairy sort of virus? Not really. In fact, it was rather lame, and couldn’t survive in the wild unless someone took special care of it and kindly provided it with what it needed to live. So what was the reason behind Bliss’s seemingly undeserved glory?

The reason is that Bliss is the only one of its kind – it is the only virus ever created for Linux. In fact, the programmer who created it posted it on a well known mailing list for programmers, admitting that it was only released as a proof of the concept that a virus could be written for any platform, but it wasn’t expected to survive in the actual environment of real computers running Linux for serious purposes.

And that was all, since that day in 1997, not a single virus has been seen for Linux. The anti-virus company McAfee tried to make much of Bliss, and released an anti-virus product for Linux, claiming that they were the ones who had found out all about it, and how it was one of the deadliest viruses known to civilization.

Which was totally untrue, because a programmer from that mailing list posted the virus to McAfee for inspection. What the company was trying to do was basically tap into the Linux computing sector with their AV business. Linux has traditionally been a sector of the market where AV companies have never made any progress, except in a special situation. McAfee were trying to remedy that by highlighting Bliss. It didn’t work, however. The Linux AV didn’t sell at all, and till date no computer in the world has been destroyed by this ‘deadliest of infections’.

What makes Linux so good? Apart from its inherent security model that is built into its kernel (which is the heart of the operating system), Linux is created as a multi-user system from the ground up. There is one administrator called root, who has the permission to do anything with the system. All normal users have write permission only in their respective ‘home directories’, which do not contain any system files. So any Linux virus, even if it existed, would only be able to work within the user’s home directory. Linux users are trained from the very beginning not to log in as root unless there’s some serious system-level work to be done. So the virus never has a chance of infecting the system.

The same could work for Windows if users could be trained enough to create unprivileged accounts for themselves and work with those when doing normal work. But Windows does not encourage this, because there are several everyday tasks like installing new programs or running defrag, which need administrative rights.

So if you have been made miserable by viruses, you can either burn a pocketful of bucks on the latest AV solution, or you could switch over to Linux and forget the whole sorry business for the rest of your life.

Beware of worms in your computer. When I say worms, in case you are a complete newbie in the field, you should know that they are not real worms. Worms are, in fact, a kind of program which enter your pc. You will never know, but in your computer will reside a program foreign to your needs. And in probability it, or more likely they will steal your delicate information for somebody with doubtful motives.

Does that sound like a thriller in the making? Well, it should, but also, it is the truth. Last year, bank frauds cost decent people around the world billions of dollars. And most of the money that got siphoned was lost due to faulty security. Your computer might be the next target.

Unaware, you might invite that Trojan Horse which will ruin your finances for good for the rest of your life. Therefore, be careful. Do not let worms into your computer as you would never let worms in your food.

But you must know about worms first. What are they actually? Are they viruses? Or are they like spyware?

In a way they resemble viruses, but in another way they are even deadlier than a virus. For, what a virus does is, it lodges itself into a program. It becomes dependent on that specific program. It, of course, has the capabilities of ruining your database, but it still needs a medium to propagate itself. A worm, however, is a different cup of tea altogether. A worm propagates without the need of a medium. And that is why it is, often, more dangerous than a virus. Because it is a virus without a few weaknesses of the computer virus.

What happens in this case is, while a virus must spread itself through other programs, mails and such, a worm can independently replicate itself throughout a system. This makes a network very unstable. The threat is that, once you have a system of computers connected to each other, one of the computers getting a worm through the internet would potentially threaten all the computers in the system.
The name ‘worm’ comes from a 1975 science fiction by John Brunner called The Shockwave Rider. There was a striking similarity found between what Brunner described and the ‘worm’ as it is to be found now.

The first worm in the world was created by a team of computer engineers at Xerox PARC as early as 1978. The intention then was, however, beneficial. It was a program, which was designed to search through a network, find idle machines, and divide the workload equally to them. This was of course, for the benefit of the network. However, this scenario changed when in 1988 Robert Tappan Morris, a graduate student at Cornell University devised a similar program,, yet with a different agenda. Morris received three years of probation, 400 hours of community service and a hefty fine.

It is always judicious to use a firewall and a secure operating system and a secure browser when you have to surf the net extensively. Because, once a worm gets in, it is very hard to cleanse your system.

Anyone who downloaded the Vietnamese language pack for Firefox 2 needs to run an anti-spyware and anti-virus scan, then disable the pack for now. Mozilla warned yesterday that all versions of that language pack downloaded from its servers since Feb. 18, 2008, were infected with pop-up ad serving software.

Window Snyder, Mozilla’s chief security officer, said the Vietnamese language pack was contaminated as the result of a virus infection. “This usually results in the user seeing unwanted ads, but may be used for more malicious actions.”

Snyder said Mozilla doesn’t know how many people downloaded the compromised language pack, but said there have been 16,667 downloads of the pack since November 2007.

Mozilla is working on getting a replacement language pack up on the site soon. Snyder said that while Mozilla does virus scans when add-ons are uploaded to its servers, the scanner for whatever reason didn’t catch this nasty until several months after the upload. Mozilla is now adding post-upload scans to everything on its download servers, she said.

Language packs are add-ons in Firefox. Add-ons can be removed by clicking “Tools” and then “Add-ons.” According to the discussion on this in the Bugzilla database, the culprit here is something called “Trojan.Win32.Xorer,” which disables security software on the infected PC and spreads by infecting files, programs and removable drives.

The Vietnamese language pack for Firefox 2 contains inserted code to load remote content. This code is the result of a virus infection, but does not contain the virus itself. This usually results in the user seeing unwanted ads, but may be used for more malicious actions.

Everyone who downloaded the most recent Vietnamese language pack since February 18, 2008 got an infected copy. While we cannot determine the exact number of compromised downloads, there have been 16,667 total downloads of the Vietnamese language pack since November 2007, so we anticipate the impact on users to be limited.

Mozilla does virus scans at upload time but the virus scanner did not catch this issue until several months after the upload. We are also adding after-the-fact scans of everything to address this sort of case in the future.

A new language pack will be available shortly. Until then, Vietnamese language pack users should disable this package using the add-ons dialog on the Tools menu.

https://bugzilla.mozilla.org/show_bug.cgi?id=432406

source:blog.washingtonpost.com/securityfix/2008/05/mozilla_distributes_virusinfec_1.html

There are many programs out there that can help you with Spy ware and Mal ware protection.

Some of the best programs to us are as follows;

The Cleaner Trojan checker For Trojan checker.
Male-ware Protection – http://www.malwarebytes.org/mbam.php
AVG – Offers free virus protection for your pc without causing vulnerabilities

Many other are available but be sure you get them from reputable services. All information secured on hard drives makes some people thing they are secure. They are NOT if they do not follow the simple instructions to avoid opening up our computer to malicious attacks.