Search the FAQ Archives

3 - A - B - C - D - E - F - G - H - I - J - K - L - M
N - O - P - Q - R - S - T - U - V - W - X - Y - Z - Internet FAQ Archives

[alt.comp.virus] FAQ Part 4/4

( Part1 - Part2 - Part3 - Part4 )
[ Usenet FAQs | Web FAQs | Documents | RFC Index | Houses ]
Archive-name: computer-virus/alt-faq/part4
Posting-Frequency: Fortnightly
Maintainer: Co-maintained by David Harley, Bruce Burrell, and George Wenzel

See reader questions & answers on this topic! - Help others by sharing your knowledge

               alt.comp.virus (Frequently Asked Questions)

                       Version 1.1 : Part 4 of 4
                      Last modified 19th August 1999

                     `6_ 6  )   `-.  (     ).`-.__.`)
                     (_Y_.)'  ._   )  `._ `. ``-..-'
                   _..`--'_..-_/  /--'_.' ,'
                  (il),-''  (li),'  ((!.-'


- ----------

This document is an honest attempt to help individuals with computer
virus-related problems and queries. It can *not* be regarded as being
in any sense authoritative, and has no legal standing. The authors
accept no responsibility for errors or omissions, or for any ill effects
resulting from the use of any information contained in this document.

You should not assume that all or any information in this document
is up-to-date.

Not all the views expressed in this document are those of the maintainers,
and those views which *are* those of the maintainers are not necessarily 
shared by their respective employers.

Copyright Notice
- ----------------

Copyright on all contributions to this FAQ remains with the authors
and all rights are reserved. It may, however, be freely distributed
and quoted - accurately, and with due credit. 

It may not be reproduced for profit or distributed in part or as a whole
with any product or service for which a charge is made, except with
the prior permission of the copyright holders. To obtain such permission,
please contact one of the co-maintainers of the FAQ.

  	 David Harley  <>
        George Wenzel <>
        Bruce Burrell <>

[Please check out the more detailed copyright notice at the beginning
of part 1 of the FAQ]

- --------------------------------------------------------------------------


See Part 1 of this FAQ for the full Table of Contents

  Part 4

 (14)    Miscellaneous

 Are there anti-virus packages which check zipped/archived files?
 What's the genb/genp virus?
 Where do I get VCL and an assembler, & what's the password?
 Send me a virus.
 It said in a review.....
 Is it viruses, virii or what?
 Where is alt.comp.virus archived?
 What about firewalls?
 Viruses on CD-ROM.
 Removing viruses.
 Can't viruses sometimes be useful?
 Do I have a virus, and how do I know?
 What should be on a (clean) boot disk?
 How do I know I have a clean boot disk?
 What other tools might I need?
 What are rescue disks?
 Are there CMOS viruses?
 How do I know I'm FTP-ing 'good' software?
 What is 386SPART.PAR?
 Can I get a virus to test my antivirus package with?
 When I do DIR | MORE I see a couple of files with funny names...
 Reasons NOT to use FDISK /MBR
 Why do people write/distribute viruses?
 Where can I get an Anti-Virus policy?
 Are there virus damage statistics?
 What is ICSA approval?
 What language should I write a virus in?
 No, seriously, what language are they written in?	
 [DRD], Doren Rosenthal, the Universe and Everything
 What are CARO and EICAR?
- -------------------------------------------------------------------

(14) Miscellaneous

Are there anti-virus packages which check zipped/archived files?
- -------------------------------------------------------

More and more anti-virus programs are scanning within zipped, 
packed, or archived files.  The specific archive formats supported
will vary from product to product - check with the makers of the
product for details.  Some products will check recursively within
archives, meaning they will scan (for example) a zip file within an
arj file within another zip file, and so on.  Scanning within zipped
files is beneficial when scanning newly-downloaded files, but it 
is simply a convenience - a product that supports more archive formats
may not be better suited to your needs, especially if you never use
files archived with those formats.  Products that scan lots of archive
types are generally most useful for people who run software archives or
other large collections of zipped/archived files.

What's the genb/genp virus?
- ---------------------------

This is McAfee-ese for "You may have an unrecognised ('generic')
boot-sector (genb) or partition-sector (genp) virus". Re-check
with a more recent version or the latest version of another
reputable package.

Where do I get VCL and an assembler, & what's the password?
- -----------------------------------------------------------

Wrong FAQ. You don't learn anything about viruses, programming
or anything else from virus toolkits. You want rec.knitting. B-)

I can't believe there's anyone left on the Internet who doesn't
know the VCL password, but I'm not going to tell you anyway.

OK, maybe you want an assembler to learn assembly-language, not
just to rehash prefabricated code. Where do you get TASM?
You buy it from Borland or one of their agents, either stand-alone
or with one of their high-level languages. If you want freeware
or shareware, I guess you can still get the likes of CHASM and
A86 (SimTel mirror sites in SimTel/asm).

Send me a virus
- ---------------

Anti-virus researchers don't usually share viruses with people
they can't trust. Pro-virus types are often unresponsive to
freeloaders. And why would you *trust* someone who's prepared
to mail you a virus, bona-fide or otherwise? [A high percentage
of the 'viruses' available over the internet are non-replicating

Requests for viruses by people 'writing a new anti-virus utility'
are usually not taken too seriously.

* We get rather a lot of such requests, which leads to a certain amount
  of cynicism.
* Writing a utility to detect a single virus is one thing: writing a
  usable, stable, reasonably fast scanner which detects all known
  viruses is a considerable undertaking. There are highly experienced
  and qualified people working more or less full time on adding routines
  to do this to antivirus packages which are already mature, and unless
  you have a distinctly novel approach, you don't have much chance of
  keeping up with them.
* It may be that the research you're interested in has already been done.
  Say what sort of information you're looking for, and someone may be able
  to help.
* You can't afford to use junk 'viruses' for research, and the best
  collections are largely in the hands of people who won't allow
  access to them to anyone without cast-iron credentials.

If you want to test anti-virus software with live viruses, this
is *not* the way to get good virus samples.

Valid testing of antivirus software requires a lot of time, care
and thought and a valid virus test-set. Virus simulators are
unhelpful in this context: a scanner which reports a virus when it
finds one of these is actually false-alarming, which isn't
necessarily what you want from a scanner.

Read Vesselin Bontchev's paper on maintaining a virus library:

There have been one or two requests for source code. Assuming you have
the necessary knowledge of programming (especially x86 assembler) and the
PC, this is probably the wrong approach, unless you're a serious
antivirus researcher (in which case you need to sell yourself to the
antivirus research community, and asking for viruses here isn't the
way to earn their trust).

* How can you trust any source code you're sent? Antivirus researchers won't
  send it to you, so you have to rely on the goodwill of a virus writer
  or distributor: not always a good idea. Many so-called viruses picked up
  from CDs, VX websites etc. aren't viruses at all.

* Are you going to examine all known viruses? Or all those listed in
  the current WildList? If not, what are your selection criteria going to
  be? How will you tell an insignificant variant from a completely different
  virus type?

Your first task is to understand the general principles, and you won't get
those from snippets of code. If you still need low-level analysis
you might like to try
where you can find analyses (without source code) of a number of common
viruses, analysed by experts.

It said in a review....
- -----------------------

Reviews in the general computing press are rarely useful. Most
journalists don't have the resources or the knowledge to match
the quality of the reviews available in specialist periodicals like
Virus Bulletin or Secure Computing. Of course, it's possible to
produce a useful, if limited assessment of a package without
using live viruses based on good knowledge of the issues involved
(whether the package is ICSA-certified, for instance): unfortunately,
most journalists are unaware of how little they know and have a vested
interest in giving the impression that they know much more than they
do. Even more knowledgeable writers may not make clear the criteria
applied in their review. 

Is it viruses, virii or what?
- -----------------------------

The Latin root of virus has no commonly used plural form. Since the 
use of the word virus is borrowed from biology, you might like to conform 
to the usage normally favoured by biologists, doctors etc., which is
viruses. However, a number of people favour the terms virii/viri,
either to avoid confusion with the biological phenomenon (but what's
the point of distinguishing in the plural but not in the singular?),
or to avoid being mistaken for anti-virus researchers.....

Bottom line, 'viruses' is the correct English plural for the singular 
'virus'.  Viri, virii, and so on are all slang.

Where is alt.comp.virus archived?
- ---------------------------------

It isn't, as far as anyone seems to know. No-one currently working on
the FAQ is likely to offer archiving, since a full archive would
include uploaded viruses. 

Tom Simondi points that there is an archive of sorts at Dejanews. You
can search for several months of messages by subject at:

What about firewalls?
- ---------------------

Firewalls don't generally screen computer viruses, though some firewall
products may allow for virus-scanning plug-ins. There are also
"viruswalls" that scan for viruses at the Internet gateway. 
Some such products can scan incoming and outgoing E-mail
attachments, ftp'd or http'd files etc. for viruses.  MIMESweeper, 
uses yout favourite scanner for scanning the viruses after it has 
opened up the E-Mail attachments in a secure area on the hard drive 
of the NT machine.  Obviously, the on-demand scanner is an additional 

MIMESweeper has advanced content filtering abilities which go beyond
its capabilities (with assistance from other software) for detection
of file viruses and trojans.

These products do real scanning before the mail hits the workstation
hard drive but make sure your mail attachments, WWW downloads etc. can't 
be automatically executed and use a good TSR/VXD in combination with a 
good on-demand scanner.  

Note that realtime virus scanning at the gateway can add a heavy network 
overhead and probably won't catch as many viruses as checking *all* 
files from *all* sources with a desktop scanner.

Current informed thinking tends to be that detection of viruses at
the firewall is acceptable (1) if you can afford the additional
hardware, software and latency (processing overhead), not to mention
the hidden administrative overheads of configuration and policy for
dealing with boundary conditions such as unusual 7-bit encoding formats,
encrypted files etc. (2) as long as you appreciate that it can only be 
supplementary to checking at the desktop, not a replacement. Mail
attachments, FTP and HTTP are more significant vectors for virus
transmission than formerly, especially with the near-exponential
boom in macro viruses, but other vectors (especially floppy disks)
are still of vital concern. System administrators are attracted by
the fact that it's easier to update server software than control
the use of scanning on individual workstations, but the fact remains
that in most environments, until the desktop is adequately protected
with good, up-to-date realtime (on-access) scanning and/or scheduled
on-demand scanning, virus scanning at the perimeter is a 

For firewall-related information see the newsgroups

or, if you don't mind your mail by the ton, the firewalls mailing-lists.


Marcus Ranum's firewalls FAQ:      


   Firewalls and Internet Security - Repelling the Wily Hacker
   (Cheswick, Bellovin) - Addison-Wesley

   Building Internet Firewalls (Chapman, Zwicky) - O'Reilly

Viruses on CD-ROM
- -----------------

Viruses have been distributed on CD ROM (for instance, Microsoft
shipped Concept, the first (in the wild) macro virus, on a CD ROM called
"Windows 95 Software Compatability Test" in 1995).  It is wise to scan CD
ROMs on arrival for viruses, just like floppies.  If the CD ROM has
compressed or archived files it is wise to scan it with an anti-virus
package which can cope with large amounts of compressed and archived

If you scan all drives at every boot, though, you may find that this
gives you a good incentive to remove CDs from your CD drive before
you power down, especially if your scanner isn't set to allow you
to break out of a scan. B-)

Removing viruses
- ----------------

It is always better from a security point of view to replace infected
files with clean, uninfected copies.  However, in some circumstances this
is not convenient.  For example, if an entire network were infected with
a fast-infecting file virus then it may be a lot quicker to run a quick
repair with a reliable anti-virus product than to find clean, backup copies
of the files.  It should also be realised that clean backups are not
always available.  If a site has been hit by Nomenklatura, for example, 
it may take a long time before it is realised that you have been infected.  
By that time the data in backups has been seriously compromised.

There are virtually no circumstances under which you should need to reformat
a hard disk, however: in general, this is an attempt to treat the symptom
instead of the cause. Likewise, re-partitioning with FDISK is unnecessary.

If you use a generic low-level format program, i.e. one which isn't
specifically for the make and model of drive you actually own, you
stand a good chance of trashing the drive more thoroughly than any
virus yet discovered.

Can't viruses sometimes be useful?
- ----------------------------------

Vesselin Bontchev wrote a respected paper on this subject:
Fred Cohen has done some heavy-duty writing in the other direction.
Start with "A Short Course on Computer Viruses", "It's Alive!"(Wiley).

In general, it's hard to imagine a situation where (e.g.) a
maintenance virus is the *only* option. I have yet to see a convincing
example of a potentially useful virus which *needs* to be a virus.
Such a program would have to be *much* better written and error-trapped
than viruses usually are.

Do I have a virus, and how do I know?
- -------------------------------------

Almost anything odd a computer may do can (and has been)
blamed on a computer "virus," especially if no other
explanation can readily be found.  In most cases, when an
anti-virus program is then run, no virus is found.

A computer virus can cause unusual screen displays, or
messages - but most don't do that.  A virus may slow the
operation of the computer - but many times that doesn't
happen.   Even longer disk activity, or strange hardware
behaviour can be caused by legitimate software, harmless
"prank" programs, or by hardware faults.  A virus may cause
a drive to be accessed unexpectedly (and the drive light to
go on) - but legitimate programs can do that also.

One usually reliable indicator of a virus infection is
a change in the length of executable (*.com/*.exe) files, a
change in their content, or a change in their file date/time
in the Directory listing.  But some viruses don't infect
files, and some of those which do can avoid showing changes
they've made to files, especially if they're active in RAM.

Another common indication of a virus infection is a
change to interrupt vectors or the reassignment of system
resources.  Unaccounted use of memory or a reduction in the
amount normally shown for the system may be significant.

In short, observing "something funny" and blaming it on
a computer virus is less productive than scanning regularly
for potential viruses, and not scanning, because "everything
is running OK" is equally inadvisable.

What should be on a (clean) boot disk?
- --------------------------------------

A boot floppy is one which contains the basic operating system, so that
if the hard disk becomes inaccessible, you can still boot the machine
to attempt some repairs.  All formatted floppies contain a boot sector,
but only floppies which contain the necessary system files can be used
as boot floppies. A clean boot disk is one which is known not to be
virus-infected. It's best to use a clean boot disk before routine
scans of your hard disk(s). Some antivirus packages will refuse to run
if there is a virus in memory. It is usually better and sometimes
mandatory to disinfect a system without the virus in memory, and an
undetected file virus may actually spread faster during a scan, since
scanners normally open all executable files in all directories.

To make an emergency bootable floppy disk, put a disk in drive A and type
        FORMAT A: /S
Be careful to avoid 'cross-formatting', i.e. formatting a double-density
disk as high-density or vice versa, if you system allows this. (You should
avoid this all the time, not just when creating a boot disk. I'd also
recommend avoiding single-density and quad-density disks, and there may
be problems writing to double-density 5.25" disks on a different machine
to the one on which they were formatted, if one machine is an XT and the
other an AT or better.)

You can also make a pre-formatted floppy into a boot disk by typing
        SYS A:
I'd suggest you also COPY these commands from C:\DOS to it: ATTRIB,
RESTORE (or whatever backup program you use, if it will fit).  They may
come in handy if you can't access the hard disk, or it won't boot up.

You may be aware that if there is a problem with your boot sequence, you
can boot from the hard disk on a DOS 6/7/Win95 system while bypassing
AUTOEXEC.BAT and CONFIG.SYS. This is not as good as a clean floppy boot:
it won't help at all if you have a boot sector/partition sector infector,
or if any or all of the basic operating system files have been infected
by a file virus.

The boot disk should have been created with the same version of DOS as
you have on your hard disk.  It should also include any drivers necessary
to access your hard disk and other devices (such as a CD-ROM).  If, for 
some reason, you can't obtain a clean boot disk with the same version 
of DOS, you can often get away with booting from a (clean) disk using 
a different version, though: indeed, there are viruses which exploit a 
bug in recent versions of MS-DOS which will prevent a clean boot from 
DOS vs. 4-6. If you *do* use a different version, remember that you 
won't be able to use many of the standard DOS system utilities on the 
hard disk, which will simply return a message like 'Wrong DOS version' 
when you try to run them, and avoid the use of FORMAT or FDISK.

If you become virus-infected it can be very helpful to have backup of your
hard disk's boot sector and partition sector (also known as MBR). Some
anti-virus and disk utilities can do this. Other useful tools to include are
a small DOS-based text editor (for editing AUTOEXEC.BAT, CONFIG.SYS and so
forth), a copy of the DOS commands COMP or FC (for comparing files),
FDISK and SYS (make sure they are from the same version of DOS as you are
booting).  There is a school of thought that your boot disk should also
include your anti-virus software.  The problem with this is that
anti-virus software should be updated frequently, and you may forget to
update (and re-write-protect) your boot disk each time.  Ideally you will
have been sent a clean, write-protected copy of the latest version of your
anti-virus software by your vendor/supplier.

If you want to use the DOS program EDIT, remember that you need both
EDIT.* and QBASIC.* on the same disk.

When you have everything you need on your boot floppy and any supplementary
floppies (see below), make sure they're all *write-protected*!

How do I know I have a clean boot disk?
- ---------------------------------------

You can't usually make up a clean boot disk on a system which has been
booted from an infected floppy or hard disk. So how do you know you're
booting clean? Actually, you can never be 100% sure. If you buy a PC
with the system already installed, you can't be sure the supplier
didn't format it with an infected disk. If you get a set of system
disks, can you assume that Microsoft or the disk duplicator
didn't somehow release a contaminated disk image? (Yes, something rather
like this has indeed happened...) However, you can be better than 99%
* If you have (and use) a reputable, up-to-date virus scanner, it will
  almost invariably detect a known virus in memory (scanners can't be
  relied on to detect an unknown virus, in memory or not). If a good
  scanner doesn't ring an alarm bell, you've *almost* certainly booted
  clean. What constitutes a good scanner is another question, however.
* If you have a set of original system disks which you received
  shrinkwrapped *and* which you've never used *or* which have only been
  used write-protected, you can probably use Disk 1 as a boot disk and
  it *probably* isn't infected - after all, Microsoft doesn't use MSAV
  for jobs like this..... It has been reported, though, that DOS
  systems disks have been distributed infected, and the fact that
  they're often distributed write-enabled doesn't inspire confidence.
* You could always contact the supplier of your most-trusted anti-virus
  utility and ask whether you can send them a boot floppy to check. Of
  course, even anti-virus gurus sometimes make mistakes, but a boot
  disk verified in this way would still be worth paying for,
  especially for organizations with mission-critical systems.

What other tools might I need?
- ------------------------------

Other suggestions have included a sector editor, and Norton Utilities
components such as Disk Doctor (NDD). These are not suitable for use by
the technically-challenged - any tool which can manipulate disks at a
low-level is potentially dangerous. If you do use tools like this, make
sure they're good quality and up-to-date. If you attack a 1Gb disk with
a package that thinks 32Mb is the maximum for a partition and MFM disk
controllers are leading edge, you're in for trouble....

A copy of PKZIP/PKUNZIP or similar compression/decompression utility may
be useful both for retrieving data and for cleaning (some) stealth viruses.
The MSD diagnostic tool supplied with recent versions of DOS and Windows
is a useful addition. Heavy duty diagnostic packages like CheckIt! may 
be of use. There are some useful shareware/freeware diagnostic packages, 

Obviously, these are not all going to go on one bootdisk. When you
prepare a toolkit like this, make sure *all* the disks are

Tech support types are likely to find that an assortment of bootable
disks including various versions of DOS comes in useful on occasion.
If you have one or two non-Microsoft DOS versions (DR-DOS/Novell DOS
or PC-DOS), they can be a useful addition. DoubleSpaced or similar
drives will need DOS 6.x; Stacked drives will need appropriate
drivers loaded.

My understanding of the copyright position is that Microsoft does
not encourage you to *distribute* bootable disks (even if they contain
only enough files to minimally boot the system) *unless* the target
system is loaded with the same version of MS-DOS as the boot floppy.
Support engineers will need to ensure that they are legally entitled
to all DOS versions for which they have bootable disks.

What are rescue disks?
- ----------------------

Many antivirus and disk repair utilities can make up a (usually
bootable) rescue disk for a specific system. This needs a certain
amount of care and maintenance, especially if you make up more than
one of these for a single PC with more than one utility. Make sure
you update *all* your rescue disks when you make a significant
change, and that you understand what a rescue disk does and how it
does it before you try to use it. Don't try to use a rescue disk
made up on one PC on another PC, unless you're very sure of what
you're doing: you may lose data.

Are there CMOS viruses?
- -----------------------

Although a virus CAN write to (and corrupt) a PC's CMOS memory, 
it can NOT "hide" there.  The CMOS memory used for system 
information (and backed up by battery power) is not "addressable," 
and requires Input/Output ("I/O") instructions to be usable.

Data stored there are not loaded from there and executed, so virus
code written to CMOS memory would still need to infect an
executable program in order to load and execute whatever it wrote.

A virus could use CMOS memory to store part of its code,
and some tamper with the CMOS Setup's values.  However,
executable code stored there must first be first moved to
DOS memory in order to be executed.  Therefore, a virus
can NOT spread from, or be hidden in CMOS memory.  No known
viruses store code in CMOS memory.

There are also reports of a trojanized AMI BIOS - this is
not a virus, but a 'joke' program which does not replicate.
The malicious program is not on the disk, nor in CMOS, but
was directly coded into the BIOS ROM chip on the system board.
by a rogue programmer at American Megatrends Inc., the 

If the date is 13th of November, it stops the bootup process
and plays 'Happy Birthday' through the PC speaker. In this
case, the only cure is a new BIOS (or motherboard) - contact 
your dealer. The trojanized chip run was BIOS version M82C498
Evaluation BIOS vs. 1.55 of 04-04-93, according to Jimmy
Kuo's "What is NOT a virus" paper.

- From time to time there are reports from Mac users that the
message 'welcome datacomp' appears in their documents without
having been typed. This appears to be the result of using a
trojanised 3rd-party Mac-compatible keyboard with this 'joke'
hard-coded into the keyboard ROM. It's not a virus - it can't
infect anything - and the only cure is to replace the keyboard.

How do I know I'm FTP-ing 'good' software?
- ------------------------------------------

Reputable sites like SimTel and Garbo check uploaded utilities for
viruses before making them publicly available. However, it makes
sense not to take anything for granted. I'm aware of at least one
instance of a virus-infected file being found on a SimTel mirror:
you can't scan a newly-uploaded file for a virus your scanner
doesn't know about. Good A/V packages include self-checking code,
though it's unsafe to depend even on this 100%. Be paranoid: you
know it makes sense....

In general, don't run *anything* downloaded from the Internet,
BBSs etc. until it's been checked with at least one reputable
and up-to-date antivirus scanner.

What is 386SPART.PAR?
- ---------------------

People are sometimes alarmed at finding they have a hidden file
with this name. It is, in fact, created by Windows 3.x when you
configure it to use a permanent swap file (a way of allowing Windows
to work as if you had more memory than you really do. On no account
should you delete it, as it will upset your configuration. If you wish
to remove it or adjust the size, do so via the 386 Enhanced
setting in Control Panel. However, a permanent swap file usually
improves performance on a machine with relatively little memory.
The file is not executable as such, and reports of virus infection
are usually false positives.

Can I get a virus to test my antivirus package with?
- ----------------------------------------------------

Well, I won't send you one... Most packages have some means of allowing
you to trigger a test alert. There is a standard EICAR test file which
is recognized by some packages.

Most reputable, current anti-virus products will now alert on the EICAR
anti-virus test file.  See the following site for background on this file:
To make use of the EICAR test string, type or copy/paste the 
following text into a file called EICAR.COM, or TEST.COM or whatever.


Running the file displays the text "EICAR-STANDARD-ANTIVIRUS-TEST-FILE!".

The EICAR file isn't an indication of a scanner's -efficiency- at 
detecting viruses, since  (1) it isn't a virus and (2) detecting 
a single virus or non-virus isn't a useful test of the number of
viruses detected. It's a (limited) check on whether the program 
is installed, but I'm not sure it's a measure of whether it's installed 
correctly. For instance, the fact that a scanner reports correctly that a 
file called EICAR.COM contains the EICAR string, doesn't tell you 
whether it will detect macro viruses, for example. In fact, if I wanted 
to be really picky, I'd have to say that it doesn't actually tell you 
anything except that the scanner detects the EICAR string in files with 
a particular extension. 

The string is supposed to trigger an alarm only when detected at
the beginning of the file. Some products are known to 'false alarm'
by triggering on files which contain the string elsewhere.

[I have Chengi Jimmy Kuo's permission to reproduce the following, a
propos of the last-but-one paragraph]:

"The purpose of the EICAR test file is for the user to test all the
bells and whistles associated with detecting a virus.  And, if given
that one platform detects it, is everything else working?  It is to
enable such things as:

        Is the alert system working correctly?
        Does the beeper work?
        Does the network alert work?
        Does it log correctly?
        What does it say?
        Is the NLM working?  For inbound?  For outbound?
        Is compressed file scanning working?

Surprise MIS testing of AV security placements.

The file serves no purpose in testing whether one product is better
than another.  Previously, every product had to supply its own test
methods.  This allows for an independent standard.'

When I do DIR | MORE I see a couple of files with funny names...
- ----------------------------------------------------------------

Actually, this is in the Virus-L FAQ. Read that and post the question
to comp.virus or alt.comp.virus if you're still worried. Basically,
the answer is that MORE creates a couple of temporary files, being
considerably less efficient than the Unix utility it attempts to
emulate. Most versions of DOS since the Middle Ages support the
syntax DIR /P, which does the same job less messily. In fact,
if you have a version of DOS later than 5, you might consider
incorporating it into the environment variable DIRCMD, so that it
becomes your default on directory listings which exceed 1 screenful.

Of course, other utilities such as ATTRIB can also be filtered through
MORE like this, which may result in similar symptoms.

- ------------------------------------------------------------

Reasons NOT to use FDISK /MBR
- -----------------------------

See Section 12 in part 2 of this FAQ for further information about FDISK
with the undocumented /MBR switch. However, people with virus problems
are frequently advised, out of ignorance or maliciousness, to use this
switch in circumstances where it can lead to an inability to access your
disk drive and possible loss of data (not to mention hair and sanity).

Essentially, you should avoid using FDISK /MBR unless you have it on good
authority that it's safe and necessary to do so. In most circumstances, it's
safer to clean a partition sector with a good anti-virus program.

You should avoid FDISK /MBR at all costs under the following circumstances:

1. Under an infection of viruses that don't preserve the Partition Table
   e.g., Monkey, reported at 7.2% of the infections reported to _Virus
   Bulletin_ for December '95, the last report for which I have data
2. Under an infection that encrypts data on the hard drive and keeps
   the key in the MBR, e.g, One_half  -- reported at 0.8% worldwide
3. When security software, e.g., PC-DACS is in use
4. When a driver like Disk Manager or EZDrive is installed
5. When a controller that stores data in (0,0,1) is in use
6. When more than one BSI virus is active, in some conditions
7. When a data diddler is active, e.g. Ripper, accountable for 3.8% of
   the infections reported in the study cited above  (N.B.: while this
   case won't be fixed by AV utilities, at least one will know why
   there are problems with the drive)

- ------------------------------------------------------------

Why do people write/spread viruses?
- -----------------------------------

- From postings which have appeared in alt.comp.virus in the past:

* they don't understand or prefer not to think about the consequences
  for other people
* they simply don't care
* they don't consider it to be their problem if someone else is
* they draw a false distinction between creating/publishing viruses
  and distributing them
* they consider it to be the responsibility of someone else to protect
  systems from their creations
* they get a buzz, acknowledged or otherwise, from vandalism
* they consider they're fighting authority
* they like 'matching wits' with antivirus vendors
* it's a way of getting attention, getting recognition from their peers
  and their names (or at least that of their virus) in the papers and
  the Wild List
* they're keeping the antivirus vendors in a job

- ------------------------------------------------------------

Where can I get an anti-virus policy?
- -------------------------------------

There is some relevant material in the Virus-L FAQ document, but you'll
need to do most of the work specific to your own environment. It's worth
doing some general reading on security policies generally and getting
the distinctions straight between policies, strategies, standards,
procedures and protocols. I'm working on this in other contexts: some of
that material may eventually seep back into here.

The ICSA have a Corporate Virus Prevention Policy disk/document which can
be ordered via their web page ( for around $20, or downloaded
from Compuserve.

In the UK, the British Standards Institution have a Code of Practice for
Information Security Management which includes virus-management (BS7799).
[It's not necessarily well-regarded by practitioners, though.]

        389 Chiswick High Road
        London W4 4AL

        DTI (Dept. of Trade & Industry)
        IT Security Policy Unit
        151 Buckingham Palace Road
        London SW1W 9SS

The Dr. Solomon's web page ( has a paper on Guidelines 
for an Anti-Virus Policy by David Emm which is a reasonable starting 
point, though a comprehensive virus management policy is no small 
undertaking.  The Dr. Solomon's page may be moved to the
site in the near future, as Dr. Solomon's has been purchased by NAI.

- ------------------------------------------------------------

Are there virus damage statistics?
- ----------------------------------

Some, possibly even less reliable than the average survey on general
security breaches. Why?

* Many reported virus incidents aren't, in fact, virus incidents, as
  many a PC support specialist will confirm. There is a tendency to
  attribute any PC anomaly to a virus, among those who are not well
  acquainted with the virus arena. Unfortunately, this includes
  virtually the entire press corps and many security consultants. Also,
  some widely-used packages are noticeably prone to false alarms.
* Many actual virus incidents and other security breaches are not
  reported, due to the intervention of top management or Public
  Relations, out of fear of losing competitive advantage because of
  being perceived as badly-managed and insecure.
* Many other virus incidents and security breaches aren't reported
  because they're simply not recognised as such, or at all.
* There are no standards for reporting and assessing damage from
  viruses and other security breaches. Take the case of Christopher
  Pile (the Black Baron), who was convicted in the UK under the
  Computer Misuse Act: I have seen estimates in the UK press of
  the damage sustained by the company most affected by the viruses
  Pile spread ranging from #40,000 to #500,000, and this is an
  unusually well-documented incident. How can the average survey
  respondent be expected to make an accurate assessment?

The trouble is, there's a lot more to 'damage' than the figures
estimated for a particular outbreak.

        Cost of maintaining virus protection
        Training and maintaining a response team
        Management costs
        Cost of software licences
        Cost in time/productivity/money of maintaining upgrades etc.
        Formulating and enforcing policy
        Educating users in the issues and good hygienic practice
        Cost in time of routine anti-virus measures
        Cost in money and time of servicing false alarms
        Cost of sheepdip systems
        Cost of having part-time A/V people taking time off
        from their 'real' jobs
        Alternatively, the cost of having full-time A/V personnel
        Cost of tracking the product market, technological changes
        Formulating and enforcing a backup policy
        Development of protective systems
        Resource utilisation by undetected viruses

     Cost of specific outbreaks
        Loss of productivity
        Workstation/Server downtime
        Damage to reputation of the organization
        Damage to involved personnel
        Psychological damage - witch hunts
        Damage limitation
        Time spent cleaning up, examining floppies etc.
        Restoration of backups/reinstallation
        Replacing unrecoverable data
        Time and money spent increasing virus protection.....

However, the Poor Bloody Infantry often have to spend time and effort
persuading the Generals of the need to expend money on ammunition.
You might care to check out:

* The Information Security Breaches Survey 1996 [UK]

  [National Computing Centre, ICL, ITSEC, Dept. of Trade & Industry]

  Oxford House
  Oxford Road
  M1 7ED

  (voice) +44(0) 161 228 6333
  (fax)   +44(0) 161 242 2171

This came up with the highly suspect but much quoted average of about 
#4000 per virus incident.

* Computer Virus & Security Survey 1995 [Ireland]

  [Price Waterhouse, Priority Data Systems]

  Price Waterhouse
  Wilton Place
  Dublin 2
  (353 1) 6606700

++Added August 18th.

* ICSA have published surveys for some years. The 1999 survey is the
  best to date. 


- ------------------------------------------------------------

What is ICSA Approval?
- ----------------------

  The ICSA has a certification program for PC virus scanners which offers
  a measure of the detection capabilities of specific versions.
  In the past, ICSA's modus operandi was the subject of much
  scepticism within the antivirus community, but the current
  procedures are much improved (but not perfect, but nothing is).  
  The specific criteria are available at:

  A list of the certified products is available at:

The ICSA sponsors an Anti-Virus Product Developers consortium. The ICSA
and consortium members have created standards for anti-virus products
and the ICSA Anti-virus lab in Carlisle tests new versions of scanners
that are submitted to it and issues an "NCSA Approved" seal for those
products which past the test. 

For more information about the NCSA or for links to the members of the
AVPD consortium:

- ------------------------------------------------------------

What language should I write a virus in?
- ----------------------------------------

Choose your own squelch:

	* Karel the Robot
	* PL/I
	* dBase II
	* Get a life
	* Or my personal favourite (thanks, Bruce!)
	     "Hey, man; where can I get a copy of
	     Visual English to write some hot new virii?!?"

If you need to ask this question, you'd be better off collecting
tazos than trying to write viruses. 

No, seriously, what language are they written in?
- -------------------------------------------------

The simple answer is "Assembler, mostly (on the PC)". High-level
languages such as C and Pascal are sometimes used, as are various
flavours of command shells on various systems (Unix shell scripts,
DCL scripts etc.). Macro viruses are written in macro languages, 
surprisingly....... B-)

[DRD], Doren Rosenthal, the Universe and Everything
- ---------------------------------------------------

Doren Rosenthal offers a shareware utilities suite including a
virus simulator. Many of the AV pros in this group have a low
opinion of the Rosenthal utilities, and regard their author as
more of a virus writer than an anti-virus researcher, and are
annoyed by his habit of offering his utilities as a solution
for problems to which their relevance is not always obvious. As
discussions on Rosenthal-related topics sometimes generate 
much heat and bandwidth, some people have taken to adding [DRD]
to the subject header when posting to these threads, to make it
easier to avoid them.

What are CARO and EICAR?
- ------------------------

CARO - Computer Anti-Virus Research Organisation. Invitation-only
group of techie researchers, mostly representing AV vendors. CARO
approves 'standard' names for viruses. Some people tend to mistrust
the fact that CARO members often share virus samples: however, CARO
membership is a convenient yardstick by which other members can
judge whether an individual can be trusted with samples. In general,
users at large benefit: this way, AV vendors with CARO members can
include most known viruses in their definitions databases.

EICAR - European Institute for Computer AntiVirus Research. Membership
comprises academic, commercial, media, governmental organisations etc, 
with experts in security, law etc., combining in the pursuit of the 
control of the spread of malicious software and computer misuse. 
Membership is more open, but members are expected to subscribe to a
code of conduct. And yes, this is the origin of the EICAR test file.

EICAR has a web page at

- ------------------------------------------------------------------

End of a.c.v. FAQ Part 4 of 4

Version: PGPfreeware 6.5.1 for non-commercial use <>
Comment: PGP Key ID 0xDCC35C75 available on Keyservers


User Contributions:

Comment about this article, ask questions, or add new information about this topic:

Part1 - Part2 - Part3 - Part4

[ Usenet FAQs | Web FAQs | Documents | RFC Index ]

Send corrections/additions to the FAQ Maintainer:
George Wenzel <>

Last Update March 27 2014 @ 02:11 PM