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SEVERAL
YEARS AGO I heard an industry pundit refer to computer viruses
as the electronic equivalent of graffiti. This was annoying but
not particularly damaging. I wonder what he thinks now? Last
year (1999), encounters with malicious software, computer viruses,
worms, & Trojan horse programs resulted in approximately
$12.1 billion in damages. Certainly not the electronic equivalent
of graffiti, this is better described as the cyber equivalent
of a car bomb--destructive, indiscriminate, and costly.
Contrary to what's often portrayed
in the movies or on the six o'clock news, malicious software
has no magical powers, it won't cause you monitor to burst into
flames, or gnaw through your keyboard and bite off your fingers.
Computer viruses, Trojan Horse programs, and Worms are simply
computer programs. In order for one of them to do damage, some
type of programmatic code has to be run. In simple terms, the
only way malicious software (malware) can infect your computer
is if you:
- Run an infected program (i.e.,
.COM or .EXE).
- Boot or attempt to boot from an
infected floppy (in the case of a boot sector virus, diskette).
- Open an infected Microsoft Word document, Excel spreadsheet, Access database, Power Point presentation, or Microsoft Project
file.
- Run an infected Visual
Basic Script or Microsoft JScript, including "invisible"
ones embedded in Web pages or HTML formatted e-mail or news group
postings messages.
Threats
Understanding the threats is half
the battle in defending against malicious software. So what is
a virus? A worm? A Trojan Horse program? A hoax?
- Virus. A computer virus is a self-replicating
program containing code that explicitly copies itself and that
can "infect" other programs by modifying them or their
environment such that a call to an infected program implies a
call to a possibly evolved copy of the virus.
- Worm. A computer worm is a self-contained
program (or set of programs) that is able to spread functional
copies of itself or its segments to other computer systems (usually
via network connections).
- Trojan Horse. A Trojan Horse is
a program that does something undocumented that the programmer
intended but that some users would not approve of if they knew
about it.
- Hoax. A hoax is warning about a
nonexistent, extremely destructive, piece of malware. Hoax warnings
are normally distributed as chain letters that ask you to "pass
this warning along to everyone you know." Legitimate warnings
are not distributed as chain letters and will always include
links to the issuer's Website where additional information can
be found.
Solutions
How can you defend yourself again
malicious software? First, you should invest in a quality antivirus
program and keep it up to date. Always remember that antivirus
software is a perishable commodity and has to be updated regularly
(once a week in most cases) in order to be effective. Second,
you should practice Safe Hex religiously. You should never, ever:
- Open files or e-mail attachments
from someone you don't know.
- Open files or e-mail attachments
forwarded to you even if they are from someone you know.
- Open unsolicited or unexpected
e-mail attachments until you've confirmed that the sender actually
meant to send them.
- Open a document with macros enabled,
period.
- Boot from a floppy unless you personally
created it, write-protected it, and had it hidden in your sock
drawer since then.
Other things you should always do
are:
- Backup your computer regularly
(a tape drive is your best bet).
- Keep your antivirus software up
to date (both scanning engine & definition files).
- Scan e-mail attachments or downloaded
files before you open them.
- In the event disaster does strike,
don't panic. Very often users will do more damage with panicked
recovery attempts than a virus or Trojan horse would have.
 Third if you're
using Microsoft
Outlook or Outlook Express to read e-mail and news group
messages, make sure you install all of the available patches
and updates from Microsoft and disable scripting in messages.
To disable scripting in Microsoft Outlook & Outlook Express,
Open Control Panel|Internet Options|Security and select the "Restricted
Sites" zone. Now click "Custom Level" and set
every entry to disable except:
- "Drag and drop or copy and
paste files" (Should be Prompt)
- "Submit non encrypted data"
(Should be Prompt)
- "User Name" ("Login"
(Should be Prompt for username and password)
Now click "OK" and answer
yes to the "Are you sure you want to do this?" dialog.
Click "Apply" and then "OK" to close the
Internet Options dialog. Now open Outlook or Outlook Express,
select Tools|Options|Security, and change the default security
zone to Restricted Sites.
Conclusions
Want to know more about malicious
software and how to defend yourself against it? Then attend the
July 11 general meeting of the Danbury Area Computer Society
7 p.m. at the Danbury
Hospital Auditorium. You may download the
audience handout of the presentation from our Web site at
http://www.dacs.org.
DACS gemeral meetings are open to
the public. For more information about the July meeting or the
Special Interest Group meetings
that take place during the month, check our Website at or call
our Resource Center 203-748-4330. Coming in August: Henry Gil,
Voyetra
Turtle Beach, Inc., Digital Music.
Handouts
Anti-virus
Software Vendors
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