WHAT ARE VIRUSES?
In computer security, a computer virus is a self-replicating computer program
that spreads by inserting copies of itself into other computer programs or
documents. A computer virus behaves in a way similar to a biological virus,
which spreads by inserting itself into living cells. Extending the analogy, the
insertion of a virus into the program is termed as an "infection", and the
infected file, or program that is not part of a file, is called a "host".
Viruses are one of the several types of malicious software or mal-ware. In
common parlance, the term virus is often extended to refer to worms, trojan
horses and other sorts of malicious software.
While viruses can be intentionally destructive, for example, by destroying data,
many other viruses are fairly benign or merely annoying. Some viruses have a
delayed payload, which is sometimes called a bomb. For example, a virus might
display a message on a specific day or wait until it has infected a certain
number of hosts. A time bomb occurs during a particular date or time, and a
logic bomb occurs when the user of a computer takes an action that triggers the
bomb. The predominant negative effect of viruses is their uncontrolled
self-reproduction, which wastes or overwhelms computer resources, slowing your
computer down.
On many computers it is possible to get a virus just by going to the wrong
website, or opening an e-mail that may seem to come from a friend, but actually
has a virus in it.
Trojan horses
A Trojan horse is just a computer program. The program pretends to do one thing
(like claim to be a picture) but actually does damage when one starts it (it
can completely erase one's files).
Worms
A worm is a piece of software that uses computer networks and security flaws to
create copies of itself. A copy of the worm will scan the network for any other
machine that has a specific security flaw. It replicates itself to the new
machine using the security flaw, and then begins scanning and replicating anew.
This is why Netstop Wi-Fi hotspots include a dual layer firewall to keep your
computers laptop from spreading a work to your own computer.
E-mail viruses
An e-mail virus will use an e-mail message as a mode of transport, and usually
will copy itself by automatically mailing itself to hundreds of people in the
victim's address book. Because this e-mail seems to come from the victim, many
people open the e-mail, only to be infected themselves, and so the process goes
on....
Key Logger
A recent survey of Internet kiosks in Wellington showed that a number of the
computers were infected by a trojan horse called a key-logger, this nasty
trojan would watch people entering their passwords for e-mail and on-line
banking and then email those passwords back to a thief who could log in as the
victim and transfer money from their accounts.
Netstop computers completely wipe the history and any other software downloaded
between users, so each new user actually sits down at a completely fresh
"virgin" computer. That's the only way we could be sure that one user did not
leave a nasty surprise for the next! Beware if you're using a public computer
for on-line banking, if it's not a Netstop terminal there may be no way of
knowing if your passwords are being e-mailed off to a thief.
A computer virus will pass from one computer to another like a real life
biological virus passes from person to person. For example, it is estimated by
experts that the Mydoom worm infected a quarter-million computers in a single
day in January of 2004. In March of 1999, the Melissa virus spread so rapidly
that it forced Microsoft and a number of other very large companies to
completely turn off their e-mail systems until the virus could be dealt with.
Another example is the ILOVEYOU virus which occurred in 2000 had a similarly
disastrous effect.
Keeping on top of the threat to computers from Viruses is no easy task,
computers use by and in contact with the public are especially vulnerable, as
there are no rules about what e-mails get opened or what websites get looked
at.
Only by designing our systems from the ground up have Netstop been able to
immunise our computers from the virus threat.
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