Viruses & Antivirus
Software Quick Guide
What is a computer virus?
A computer virus is a program
intended to interrupt computing operations or destroy files. Virus is the
generic term for an infectious program. Computer viruses come in a variety
of forms:
- A File Infector Virus
Replicates and inserts copies of itself into other executable programs.
Each time an infected program is run the virus is activated, often resulting
in the infection of other programs. In some cases running an infected
program allows the virus to load itself into memory and stay active, even
after the original infected program is no longer running.
- A Boot-Sector Virus
Infects the boot sector and/or partition table of hard drives and the
boot sector of floppy diskettes. Once a virus of this type has made changes
to these system areas of your disk or diskette, it loads itself into memory
each time you start your computer or boot from the infected diskette.
Once in memory, the virus can infect the boot sector of any diskette you
use.
- A Multipartite Virus
A hybrid of the file infector and the boot sector viruses since it infects
both files and boot sectors, increasing its ability to spread.
- A Macro Virus
Self-replicating code written in an application?s macro language, and
executed in response to an event such as opening or closing a file. Once
a macro virus is running, it can copy itself to other documents, delete
files, without the user explicitly running the macro. A macro virus is
spread by having one or more auto-execute macros in a document. Opening
or closing the infected document can activate the virus macro. When the
macro is activated, it copies itself and any other macros it needs to
the application?s global macro file, where it is then available to be
spread to all open documents.
Examples of macro viruses
include the Concept Virus that infects Microsoft Word documents and the
Laroux Virus that infects Microsoft Excel workbooks. Although Concept
and Laroux are harmless (but very annoying) viruses, similar macro viruses
have been developed that are destructive.
A virus infection may cause symptoms
such as:
- Unusual or slow behavior
on bootup, or failure to boot
- Excessive disk access times
- Failure of some or all
of a program to work properly
- Unusual error messages
- Lost or garbled output
to the screen or printer
- Sudden appearance or disappearance
of files
- Difficulty reading from
or writing to a disk
- Interference in an application?s
normal file saving and file retrieval
Although a variety of symptoms
may indicate a virus infection some virus programs display no symptoms until
they finally execute, making it unlikely you'll discover them until their
damage is done. The best way to detect a computer virus, or to confirm that
a virus is the cause of problems, is by using a specialized virus detection
program.
How can you get a computer virus?
- Using your diskette in
a PC that has an active virus in its memory
- Using your diskette in
a PC that has a virus on the hard drive
- Using a virus-infected
diskette in your PC
- Running a computer program
that?s infected with a virus
- Uncompressing an infected,
self-extracting compressed file (for example, a self-extracting "zip"
file; the "packaging" around this kind of file is a program that executes
and so can contain a virus)
- Opening a document that
contains a virus.
- By opening an e-mail message
attachment that could be an executable file with a virus, a self-extracting
file with a virus, or a document file with a macro virus.
- By downloading an executable
file, a self-extracting file, or an infected document file from the
Internet.
How to avoid computer viruses while
using networked Fuqua MBA PCs
It?s important to understand
how to protect yourself against picking up a virus from one of the Fuqua MBA
PCs. Because these PCs are used by many people, you must protect yourself
from the possibility that the last user left a virus behind.
- Check your diskettes &
your H: drive regularly for viruses, using an up-to-date antivirus program.
- Before using a diskette passed
on to you from members of a study team or work group, check the diskette
for viruses.
- Before running a self-extracting
archive (such as a zipped exe file that?s designed to decompress/unarchive
into several smaller files) check it for viruses.
- Write-protect any diskettes
that you can use in read-only mode. To write protect a 3.5" diskette locate
the write-protect opening in one corner of the diskette and slide the cover
so the small square hole is open.
- Establish and use a regular
antivirus routine on your home PC.
- Make backup copies of your
important work. Keep your backups separate from your day-to-day work. If
a virus (or other misfortune) destroys an important file, you can use your
backup diskettes to recover.
- Keep your original program
diskettes in a secure place in case you need to reload your software.
- If you?re dealing with documents
from other users, take steps to prevent your software applications from
automatically executing unknown macros. You can use utilities written for
this purpose by antivirus vendors. Microsoft has released utilities of this
nature for Word and Excel; they?re available for download from Microsoft?s
software web site.
- If you don?t know where a file
has been, don?t open it in an application until you scan it. This means
any document file, whether downloaded from a bulletin board or web site,
attached to an e-mail message, or included in a shrink-wrapped package from
a commercial vendor.
How to scan & clean virus-infected files
Should you encounter technical issues, please contact the Technical Support
Center at x7878.
1. Save all your documents
2. Exit all applications
3. Click on the "start" button
4. Choose "programs"
5. Choose "Network Associates" program
group
6. Choose "McAfee Virus Scan".
- Change the "Scan in:" to the
drive letter you wish to scan
- 8. Choose "All Files"
9. Click "Action".
10. Click on the down arrow and choose
"Clean infected files automatically"
11. Click on "scan now"
How to Get your own copy of McAfee
antivirus software
Duke University has purchased
a site license for McAfee, and is available for download from both Fuqua's
and Duke OIT's web site. Instructions for how to download and install are
located at the Duke OIT site.
Please Note:
McAfee should NOT be downloaded
on any public access computers at Fuqua. They are updated by the Technical
Support Center.
Note that due to software licensing
you can only download software from Duke OIT's website when logged on to
the Duke Network or when Dialed in via DukeNet. You can NOT download it
when dialed in via your ISP (ex. Mindspring, IBM, or Earthlink)
- Go to OIT?s home page http://www.oit.duke.edu/site/
- Click on Software.
- Click on McAfee Virus Scan.
- Click on Download Software.
- Download
Now!
McAfee Associates also maintains
a home page on the world wide web. You can visit their site for more information
about their products and to download the current copy of their software. Point
your web browser to http://www.mcafee.com.
