First of all it would be useful to state that a Trojan horse virus represents an infectious program able to cause serious damage to a computer.
The Trojan horse can infect a user's machine without being noticed. As soon as it penetrates a computer, the Trojan horse scans it with the goal of stealing personal data.
One of the earliest Trojan horse viruses was detected in the 1980s when several computers were affected. As it was earlier mentioned Trojan horse viruses are created in order to steal useful information such as passwords.
They are developed by hackers, who, after stealing data, can use the information for various purposes, including blackmail. Some of the first Trojan horse viruses were able to infect Windows32 files, but since then these programs evolved, and today they can cause even more harm.
The name of the Trojan horse comes from a story from Greek mythology about the siege of Troy. Greeks were unable to conquer the city until they built a huge wooden Trojan horse and hid a number of warriors in it.
The wooden horse was supposed to be a present from the Greeks, informing that they sailed away and no longer wanted to conquer the city.
When the Trojan horse was pulled into the city, the small army of Greeks inside it waited till dark and then invaded the Troy, destroying it, thus leading to the end of the war.
In contrast to the wooden Trojan horse, the Trojan horse virus spread worldwide and is still popular today.
According to some online sources, the first Trojan horse virus was dubbed the pest trap, also known as Spy Sheriff. This Trojan horse managed to infect about one million PCs worldwide.
It did not damage any files on a computer, instead, it led to the appearance of a large number of pop-ups, most of them looking like warnings that warned users about the necessity to installs some kind of software application.
As soon as the Trojan horse computer virus was installed on the machine, it was quite difficult to get rid of it. In case the user tried to erase it, the Trojan horse would simply reinstall itself from hidden affected data files on the computer.
Often Trojan horse viruses come in packages that at first sight seem to be rather harmless. However, this is exactly what a Trojan horse should do until it affects a computer so hackers could remotely control the programs of the infected machine.
There was a popular case that involved a professor who was accused of downloading about 1,000 child porn images, but who was released after it was discovered that the professor's computer was affected by a Trojan horse virus that downloaded the pictures.
Despite the false accusations, the outcome of the situation had a serious impact on the professor's reputation.
During the 1980s there was an increase of the Bulletin Board System, which was a computer system running software that permitted users to penetrate the system through a phone line.
The BBS contributed to a fast spread of Trojan horse viruses because after users logged in, they carried out such functions as uploading and downloading a software and data sharing (some of which was infected). At that time computer viruses were created to aim popular software traders.
A dangerous Trojan horse virus was the Vundo, which used a lot of memory of the operating system at different intervals and generated a lot of pop-ups that informed the user about a number of software programs that need to be installed on the computer.
The installed software included one or more computer viruses. Unlike the Spy Sheriff, it was rather easy to get rid of Vundo.
There is one important thing to remember: a Trojan horse virus cannot be turned on unless a user doesn't activate the program that features the virus.
It is important that you do not download unknown programs, especially if someone or something persuades you to do so
As developers, we’re aware that some of the lingoes we speak as our “native language” perhaps aren’t used in the same way by those, not in the same sector.
When we talk about a Kernel Data page error we’re not discussing problems with our favourite breakfast cereals, and if you overhear us chatting about the cloud it doesn’t mean we’re debating whether one looks more like a sheep or a ball of cotton wool
– so we’re well aware there are often times (usually in the café), we might get some strange looks.
One of the most interesting terms this applies to is “Trojan” or “Trojan horse” – the original Trojans, of course, were inhabitants of the ancient city of Troy, but we hear more now of Trojans in the computing world as malicious computer programs that try to capture user data for fraudulent purposes. So why has this term become well known in the computing world?
The term “Trojan Horse” comes from the legend originating around the downfall and destruction of the city of Troy in roughly 1180 BC. After a ten year siege with the Greeks, in which the Trojans closed their gates around the city (which was also protected by massive walls) and in essence created a stalemate.
The city was virtually impenetrable and the Greeks were getting fed up; they had camped on the banks of the River Scamander (presumed to be the modern Karamenderes) for 10 long years and had made virtually no headway in gaining access to the city.
Troy still had access to the rest of Europe via the shortest point at Abydos (an ancient city until late Byzantine times) and their allies as the Greeks only controlled the entrance to the Dardanelles (one of the world’s narrowest waterways) so was never completely besieged, and as such was still able to take part in trade. Nobody was starving and the Greeks had had enough.
According to legend, Odysseus, the Greek king, and leader of his army plotted to trick the Trojans into thinking the Greeks had given up on the war.
The entire fleet of Greek ships sailed away one night after burning their camp, leading the city to believe they’d gone for good.
The gates were thrown open and the city rejoiced and partied, reveling in their freedom. Venturing onto the sands, they discovered a giant, hollow horse made from wood, inscribed with a dedication to Athena (Goddess of Wisdom & War) as a thank-offering for their same passage home.
The Trojans dragged the horse inside the walls of the city and made the horse part of the celebrations – interestingly, Cassandra (daughter of King Priam and considered insane as she made prophecies that nobody believed in) and Laocoön (Trojan priest) warned against keeping the horse but these were not heeded (and Laocoön died soon after; accordingly to legend, he was killed by sea serpents alongside his two sons).
The Greek fleet, once out of immediate sight, had turned back and were waiting at Tenedos (an island in the Aegean Sea) for a signal.
A Greek spy, Sinon, saw the moon rising and signaled the fleet to return; at the same time, Greek soldiers emerged from within the horse and set about killing the guards.
Upon return of the Greek fleet, soldiers stormed the city (as the gates had been opened by the soldiers hidden within the horse) and set about ensuring the destruction of Troy.
The Trojans put up a valiant fight but as they were disorganized and unprepared, eventually the Greeks won and the city burned.
This decisively ended the Trojan War and led to the legend of the Trojan Horse being told. The term itself is metaphorically known to mean a situation in which an enemy has tricked their foe into allowing access to a securely protected place of safety, and in computing terms, a “Trojan Horse” is a program that tricks users into willingly running it, but it is not really the program it is disguised as.
Trojan Horses, or just “Trojans”, differ from computer viruses and worms in that they do not typically attempt to take over other files; they run mainly to allow access to the device in question by unauthorized persons.
The motives of the attacker vary but typically involve data corruption, malware spread, and file modification or deletion.
Because Trojans are so versatile and can go unnoticed, their popularity has exploded until they've become the malware of choice for many online criminals.
Some of the more common actions that Trojans take are:
Creating backdoors: Trojans typically makes changes to your security system so that other malware or even a hacker can get in.
Spying: some Trojans are essentially Spyware designed to wait until you access your online accounts or enter your credit card details, and then send your passwords and other data back to their master.
Turn your computer into a Zombie! sometimes, a hacker isn't interested in you but just wants to use your computer as a slave in a network under his or her control.
Send costly SMS messages: even smartphones get Trojans, and the most common way for criminals to make money is by using them to make your phone send costly SMS messages to premium numbers.
Well, that’s just it: Trojans can look like just about anything. The computer game you downloaded from a strange website. The "free" MP3 song by that band you secretly like. Even an advertisement might try to install something on your computer.
Some Trojans are specifically designed to trick you into using them. They can use misleading language or try to convince you they are a legitimate app.
Tricking you this way is called social engineering because the criminals designed a situation to make you act against your interest.
Staying away from questionable sites, pirated materials, and dubious links may help, but in the long run, something will get through.
If you truly want to stay protected, you need an anti-malware software like AVG AntiVirus FREE to stay protected.
Even security experts rely on some form of protection to keep them safe. So should you