September 2001
Computing for the Bewildered. By Bill Hayles
Hello again.
Those of you who have been paying attention will be expecting the
second part of my ramblings about the Windows Operating System. However,
I am postponing that for a month, as one topic, for those of you who
have your own computers, has been dominating my post box recently. The
topic of that of Computer Viruses.
I'm sure that the real damage these beasties cause is far outweighed
many, many times by the worry and anxiety suffered by those who wonder
if they have one, what it will do, and what they can do about it.
If you use any other computer than a PC running Windows, then you are
fairly safe. Not because viruses aimed at MacOS or Linux systems can't
be written, but because virus writers aren't bothering, concentrating
instead on the widest "market" - the Windows based PC.
WHAT IS A COMPUTER VIRUS
A computer virus is simply a piece of code - a program - which finds
its way onto your computer uninvited, usually by pretending to be
something else. It will have a "payload", in other words, it will be
written to make your computer behave in an unwanted manner. The
payload may be merely a nuisance, such as a message appearing on your
screen periodically, or, at the opposite extreme, if can wipe all the
data off your hard disk or, (even worse in my opinion), transfer it to
another unknown computer. That's what a virus CAN do. What it CAN'T do
is to physically damage your computer, or you.
HOW DO I "CATCH" ONE
A virus can only find its way onto your computer from an external
(computing) source. A computer that is never connected to the
Internet, nor ever reads a floppy disk or CD-ROM cannot get a virus.
Nor is it of much use. Until a couple of years ago, viruses mainly
spread through floppy disks - a friend might "lend" you a piece of
software. His computer had a virus, and yours was infected through the
floppy. The more "dodgy" the software, the more likely an infection.
Infection through commercially sold software is not unknown, although
it is very rare.
Today, the vast majority of viruses arrive on your computer uninvited
through the Internet. There are different types of virus, such as
worms and trojans, but they all have one thing in common. They come in
through your Internet link. There are three main ways.
(1) Directly, through an undetected connection. All the time you are
connected to the Internet, the Internet is also connected to you, and,
unless you take precautions, anybody who wishes to can hack into your
system and upload a virus program onto it. Fortunately, since most
people don't have a permanent connection, this method is very hit and
miss for the hacker, and is thus comparatively rare.
(2) In a piece of software. This is the same as using an infected
floppy. You go to a so-called "warez" site, where software that would
otherwise cost you a considerable sum is available for free.
Unfortunately, as well as the required software, there may be uninvited
guests.
(3) IN AN E-MAIL ATTACHMENT. This is nowadays the most common sort of
virus, and the one that causes the most worry. The e-mail may well be
from somebody you know. Unfortunately they have a virus, and one of
the things it does is to attach itself to every e-mail they send (or
even sends itself, using your friend's Address Book) hoping you'll open
it because you trust your friend.
So, a some of golden rules:
(1) Only send e-mails using plain text, not HTML. Although HTML code is
in itself not usually the source of a virus, it can trigger the
execution of attachments which MAY contain the virus.
(2) Never open any attachment without checking it first (more below).
Therefore, disable any "automatically open attachments" option,
especially if you are using HTML despite (1) above
Even if an attachment IS a virus, it will do no harm if it is deleted
without ever being executed (opened)
(3) Never assume that a message from someone you know is "safe".
HOW CAN I PROTECT AGAINST VIRUSES?
It is impossible to guarantee you will never be sent a virus. If you
want such a service, a few ISPs will check all incoming e-mails for
you, and remove any that appear to contain a virus. Some of us have
misgivings about this censorship of traffic, but the companies are
quite open in what they do, and you may be one of those who find such a
service reassuring.
However, in my opinion, by far the best way to protect yourself is to
use two programs - firewall and a virus checker. The firewall will
protect against unauthorised attempts to contact your system while you
are on line. It may well also check your e-mail and "quarantine" any
suspicious attachments. A virus checker checks software already on
your computer, looking for suspicious "fingerprints" which reveal rogue
programs.
Arguments rage as to which are the best firewall and virus checking
programs. These arguments are mainly academic. All anti-virus and
firewall software works well if kept up to date. Even the greatest is
worse than useless if it is not periodically updated, ideally every
month but at least every three months. I say worse than useless as if
you have no protection software then you are at least aware that you
are vulnerable. If you have out of date software, you may be lulled
into a false sense of security, thinking you are protected when you're
not.
WHAT IF I THINK I'VE GOT ONE
As Corporal Jones said, don't panic! If you can, scan your system with
up-to-date anti-virus software. If you can't, download one from the
Internet. Don't worry about infecting "The Internet" - you won't. If
you're really worried, e-mail me - but nobody else, as you may pass on
any infection. My system is fortress guarded against viruses. If your
e-mail contains a virus, then at least I know what I'm dealing with! If
I can help, I will. I give priority to please for help with virus
problems when it comes to allocating my time.
You will notice that I haven't named any products, or given any URLs
(addresses). By the time you read this I will have put some useful links
on my website, http://billnot.com, which will enable you to download
free anti-virus and firewall software.
That's it for another month. Next month, I'll give you the second part
of the "What is Windows" saga. By the time you read this, my Saturday
morning classes will have restarted,at 1030 at The Oasis Centre, the
first being on Saturday, 15th September . The second is on Saturday
29th September The sessions are intended for absolute beginners, who
don't know the difference between the World Wide Web and a spider's web.
If you know absolutely nothing about computers and the Internet, but
want to, these sessions are aimed at you. Details are will be on the
Internet at http://billnot.com. You're welcome simply to turn up. It's
worth it for Ann's tea and biscuits alone!
If you have a question you'd like me to answer in the column, please
e-mail it to questions@billnot.com, If you don't have e-mail, you can
always leave your question at the CopiShop. However, I can't guarantee
to answer questions personally.
If you have been, thanks for reading this.