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 Identifying
a threat Minimising
a threat Symptoms
of an attack
Identifying
a threat
Floppy
disks and CDs brought into an
organisation [including
shrink-wrapped software from
original manufactures, disks from
other organisations [suppliers,
marketing agencies, etc.] ] bring
with them the risk of virus
infection. The movement of floppy
disks and CDs between different
sites within an organisation may
also help to spread a virus. Boot
sector viruses [which spread via
floppy disks] are still common;
and viruses have been found on
CDs.
Desktop
PCs used at home [and laptop PCs]
are a potential source of virus
infection. The use of laptop PCs,
in particular, has become
commonplace in the last few
years. Floppy disks and CDs used
in these PCs may not have been
checked for viruses. And the
employee may not be the only
person using the PC [spouse,
children, friends, etc.]. It is
important to recognise that these
PCs, which are not under the
direct control of an
organisation's IT Department, may
be more exposed to virus
infection than those which are
under the direct control of the
organisation.
- The
use of e-mail within corporate
organisations provides an
effective way for viruses to
spread. It is not possible to
become infected by a virus simply
by reading a text message [in
spite of the many virus hoaxes
['Good Times', 'Irina', 'Penpal
Greetings', 'Deeyenda',
'AOL4FREE', 'Join the Crew',
etc.] which supposedly spread via
text messages] ]. However, e-mail
attachments are a potential
threat. Since the advent of macro
viruses, which infect documents
and spreadsheets, e-mail has
become a very effective mechanism
for spreading viruses If a
document or spreadsheet is
infected, it can become
widespread very quickly by being
attached to an e-mail message.
This is true even of an e-mail
system, with no connection to the
outside world. If users are able
to send and receive e-mail via
the Internet, the threat becomes
even greater.
- Use
of the Internet is a further
potential source of infection. If
any users within an organisation
have direct access to the
Internet [this includes access to
CompuServe, America Online, the
World Wide Web, etc.] they are
able to download a vast range of
material [including programs and
documents] . . . all potentially
infected. Any file downloaded
could contain a virus; either an
executable file virus or a macro
virus. Unprotected access to the
Internet can provide a virus with
a springboard within your
organisation.
Back to the Top
Minimising
a threat
- Taking
regular backups of data on
your system is the most important
precaution you can take against
data loss, whether that data loss
is the result of hardware or
software malfunction, or virus
infection.
- You
should ensure that ALL incoming
software comes from reputable
sources. It is a common,
though mistaken, belief that
shareware, free disks or games
are the only source of viruses.
- Floppy
disks are a common means by which
viruses are spread [boot sector
viruses, which represent a large
proportion of the viruses
reported to Prognet, can be
spread only on floppy disks].
- Always
Write protect your Boot
disk.
- Don’t
allow external floppies
without Virus checking.
- If you
have a Hard disk, never
Boot it from floppy.
- Enable the
Boot Sector Virus
protection option in
CMOS.
- Discourage
users from leaving floppy
disks in the drive when
PCs are switched off, to
prevent PCs from being
inadvertently booted from
a floppy disk infected
with a boot sector virus.
- Judicious
network management can go
a long way towards preventing the
infection of files stored on a
network. By setting files
to 'execute-only', the network
supervisor can ensure that users
are able to run software without
being able to change it.
Back to the Top
Symptoms
of an attack
- According
to an anti-virus package, several
files on the computer are
infected, all with the same virus
- Windows
95 refuses to use 32 bit disk
access, or 32 bit file access
- If
you try to save a Word for
Windows document (using File|Save
As), the options are greyed-out.
You cannot select the drive,
folder or directory in which to
save the file; and 'Document
Template is the selected option
in the 'Save File as Type' box.
- Reduction
in memory Size.
- Unusual
File Size increasing and
decreasing.
- Boot
failures and System Crashes.
- Unusual
messages in Screen and Printer.
- Slower
operation of System.
- Longer
unusual disk operations.
- Files
may not run properly.
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