Whether it be from the movies or from history class, one of the most well known
stories is the Trojan War. In the story, a giant horse was created that looked
innocent to the Trojans, but was in fact hiding Greek warriors who took the
city of Troy while its residents were asleep. If we look at this in computer
terms, a Trojan is designed in a similar manner. They are used to trick you
into thinking you are installing a legitimate, and safe, application but you
are in instead installing a piece of malware that will perform harmful actions on your
computer without your permission or knowledge.
As a more detailed description, Trojan Horses are programs that disguise themselves
as harmless and beneficial programs but instead have a hidden purpose that you
are unaware of. Examples of the types of actions that a
Trojan may perform are:
- Delete files and data
- Lock you out of your computer
- Install backdoors so remote users can access your computer remotely.
- Execute commands on your computer
- Encrypt all of your data and then blackmail you in order to receive the
key to decrypt them.
- Download and install other malware
- Log the keystrokes you make on the computer.
- Steal passwords that you enter into certain types of sites.
- Restart your computer
- Turn off programs such as firewalls and anti-malware programs.
- Take screen shots of what is running on your computer.
- Take screen shots using attached web cams.
- Apply security patches to your computer.
- Make annoying sounds on your computer.
- Display images on your computer
- Eject your CD Tray.
- Print documents on your printer.
As you can see from the above examples, not all of them are harmful, but
they are all unwanted. Examples of how Trojans masquerade as beneficial programs
- Fake Video Codecs
- These Trojans masquerade as video codecs that you need to install in order
to view certain, typically porn related, videos on the Internet. Once installed,
these trojans will install a variety of malware including rogue anti-spyware
Warez Key Generators and Cracks
- Using programs on the Internet that state they provide serial numbers or
cracks so that you can use protected and copyrighted software is not only
illegal, but typically foolish. Most of these software are in fact Trojans
that install backdoors, keyloggers, worms, and other malware. So, you may
be saving a few dollars by not buying the software, but in the long run it
may hurt much more when someone steals your information and performs identity
Games and Game Updates
- It is not uncommon for a malware writer to create a very sophisticated game
that may actually be fun, but in reality is a shell to hide malware that it
will install on your computer. For example, in 2001 a game was being distributed
via email called Whack-a-mole that was a game where you tried to whack a mole
that pops up out of the ground. What the unsuspecting player did not know
is that when they played the game it installed a Trojan that allowed a hacker
to get into your computer remotely and access all of your documents and files.
- Let's face it, the screen savers that come with Windows are not the most
awe inspiring. Due to this, it is not uncommon for people to search for screen
savers on the Internet and install them on their computer. Unfortunately without
the proper safeguards, this screen saver may actually be a Trojan Horse that
while showing little dogs playing on your screen, is actually deleting all
of your files.
Trojans are scary, and as you can see from the descriptions above, it can be
very hard to determine what is a legitimate program and what is a Trojan hiding
in disguise. We are not, though, saying that you should stay away from downloading
interesting programs on the Internet, downloading new screen savers, installing
audio or video codecs so you can view the latest formats, or just enjoying the
Web to its fullest. We are saying that you should do so with caution and education.
This includes, in no particular order:
- Do not run programs from people you do not know.
- Even if you do know the person, before using the program you should first
scan it using your antivirus software or online tools such as VirusTotal
or Jotti because not all of your
friends are as smart as you.
- Make sure you have an Anti-Virus program, an Anti-Spyware program, and a
Firewall running on your computer.
- Don't look at porn on the web as the vast majority of these sites contain
something you don't want to catch. Sorry!
- Dont use illegal cracks or key generators. The majority is not what you
think they are.
- Use sites like SiteAdvisor to determine
if a site you are downloading or installing from is legitimate or a known
- Do not open e-mail attachments that end with .exe, .bat, .pif, or .com as
these are almost always bad.
- Read the license agreement for any programs you install. Many free downloads
are offered with spyware and other programs that you DO NOT want on your computer.
Reading the agreement may help you to spot them.
Enjoy your computer and the Internet, just be safe doing so!
Below you can find screen shots of various Trojan activities and installers.
Trojan displaying a fake Windows Security Center warning
For more screen shots of this infection click on the image above.
There are a total of 2 images you can view.