A virus is a piece of
software that is able to spread from computer to computer, or from system to
system. It is also responsible for damaging, slowing or corrupting a computer.
A virus will often piggyback on a piece of software. So for example, if you
download music or a video, then it may piggyback on that. Alternatively, you
may receive a file attachment that you download from an email and have it
piggyback on that.
Aren't viruses big
programs?
Actually, they can be
very small programs of just a few MB. This is especially true if the virus is
built to disable or freeze your computer. All it needs to do is start a
none-stop cycle that continues on until the computer freezes up. This is a very
easy task that many programmers often make by mistake. The hard part is getting
the virus software past the user's virus protection, and then getting it
installed within a system that is important to the computer. If it can also
change the settings on the computer so that the computer starts the virus when
the computer boots up, then the computer owner will need serious repairs. The
best defense is to get yourself some sort of virus protection software.
How long does the virus
take to cause problems?
It may start to corrupt
and damage your computer from the moment that you start the download, or it may
wait quite a while. It is often part of another program, so you would have to
start that other program in order to activate the virus. For example, you may
receive a few PDF files from work and may not look at them for months. However,
when the unsuspecting worker looks at the files, he or she is infected with the
virus. The worst thing is that the virus is reactivated every time the PDF is
used, and the user has no idea about it all.
An email virus
There are some very
sophisticated viruses that will activate when you open the email. The code for
the virus function is not particularly complex, but the act of getting past
email services virus screening is quite difficult.
The most common virus on
an email is one that comes via an attachment. This may be anything from a
spreadsheet to a video file. The virus is harder to identify via email services
virus screening or an anti-virus program because they cannot often read the
contents of every email attachment. Again, the user will unknowingly use the
attachment and find themselves with a virus.
Many email viruses will
go through your address book and find other peoples email addresses. They will
then send the same email to people you know, but will do it with your email
address attached. This will make the email look like it is from you, and so the
unsuspecting user will open it and be infected himself/herself.
A Trojan horse virus
This is a virus that
tells you it is doing one thing whereas it is actually doing another. It may
even look as if it does something else until you actually use it and it causes
damage to your computer. Whether this is a virus in the true sense of the word
is unclear, as a Trojan will not often replicate itself automatically.
The Trojan horse virus
may be a little more insidious as it may still run a program that does as it
claims to do, whilst also running the virus at the same time. This will help to
ensure that the Trojan program is not automatically flagged as dangerous, and
will help to ensure that you keep on using the program over and over again.
A worm has different
techniques
A worm may search for
security holes and manipulate them, moving from one to the other. Or, it may
simply scan for useful information such as email addresses, which it may then
use to spread itself into other networks.
Protect your computer
and personal data with anti-virus software from www.softforus.com
Article Source: http://EzineArticles.com/?expert=Denise_Beresford
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