PC Security - Trojan Horse Viruses
Trojan horse viruses got their name from the siege of
Troy, when the Greeks placed a large wooden horse outside the gates of Troy.
The Trojans assumed it was a peace offering from the Greeks, and moved the
horse inside the gates. The wooden horse was of course filled with hidden
warriors, and once inside the gates, they broke out of the horse, and demolished
the Trojans. Trojan horse programs work the same way.
Trojan horses can destroy files and data, but commonly contain spyware, and
even backdoor programs. Trojans are usually contained in software downloads
from unknown or untrusted sources. Some people don't consider a trojan horse
to be a virus, because it does not reproduce itself as a virus does, however
it's ability to destroy files and install programs without the user knowing
do indeed make it a virus.
When a trojan horse is being used as spyware, it monitors your computer
activities, and may even record keystrokes. This information is then sent
to a third party, without you being aware of it. It may also cause pop up
ads to display on your computer. The real danger is that information such
as passwords and credit card and banking information can be delivered to
that unknown third party, opening you up for identity theft.
When the trojan horse installs a backdoor program, it sends information to
the third party, making it possible for hackers to get into your system,
via the backdoor, and to use the system just as if it were their own. They
will often do this to look around your hard drive for information, but may
also use this to send spam with your email client, from your email address.
It is important to note that not all hackers are bad. Many of them are quite
reputable, and would never harm a system, or use it for devious purposes.
In fact, many financial institutions hire hackers in order to find security
holes in their system to make it safer. Crackers on the other hand, are a
danger. This group of people do indeed break into systems with the intent
of causing harm, and they often write malicious programs as well.
Again, trojans may be distributed via free software downloads, but they can
also arrive via email attachments, just as other viruses and worms do. You
should also be careful about opening attachments from unknown sources, and
also from downloading free software from unknown sources. If the software
has a .exe extension in the file name, be especially careful.
These days, trojan horses can even be embedded in image files. People commonly
send photos to each other online, and this is dangerous in every aspect,
unless you know the person, and you know that they take precautions against
viruses, worms, and trojan horses as well. Even then, you still run a risk.
One of the most well-known trojan horses is called Sub7. Sub7 will allow
you to remotely control your own computer, but it allows others to as well.
Never install any such software on your computer!
Some of the better brands of anti-virus software will detect, block, and
even remove trojan horses. It is vital that you ensure that your virus checker
does indeed do this, and it is also vital that you keep the virus definitions
up-to-date. Again, always be cautious when opening email attachments, and
when downloading free software.
PC Security: Index
Stopping Spam Part 1
Stopping Spam Part 2
PC Security: Spam
Email Security and Spam
Protecting Computers From Viruses
Trojan Horse Viruses
Removing a Virus
Cell Phone Viruses
Firewalls Part 1
Firewalls Part 2
Security: Parental Control Software
Malware - Spyware and Adware
Pop Up Windows
Security: Safe Public Computer Use
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