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I N T E G R I T Y M A S T E R (tm)
Version 2.22
An easy to use, data integrity and anti-virus program which also
provides PC security, change control and disk error detection.
Users Guide plus Data Integrity and Virus Guide
________________________________________________
Copyright 1990 - 1994 by Wolfgang Stiller
All rights reserved
___________________
Stiller Research
2625 Ridgeway St.
Tallahassee, Florida 32310
U.S.A.
Electronic mail to:
CompuServe: 72571,3352
Internet, Bitnet, etc.: [email protected]
Uunet: uunet!compuserve.com!72571.3352
Integrity Master (tm) - 2 - Version 2.22
Fourth Edition May 1994
Copyright 1990-1994 Wolfgang Stiller. All Rights reserved.
The following paragraph does not apply where such provisions are
inconsistent with law:
Stiller Research provides this document "AS IS" without warranty of
any kind, either express or implied, including, but not limited to the
warranties of merchantability or fitness for a particular purpose.
This document may include technical inaccuracies or typographical
errors. We continually update and correct this document with the
latest available information.
Note to U.S. Government users: Use, duplication, or disclosure by
the U.S. Government of the computer software and documentation in
this package shall be subject to the restricted rights applicable to
commercial computer software as set forth in subdivision (b)(3)(ii) of
Rights in Technical Data and Computer Software clause at 252.227-
7013 (DFARS 52.227-7013). The manufacturer is Stiller Research,
2625 Ridgeway St., Tallahassee, Florida 32310-5169.
Integrity Master and Integrity Advisor are trademarks of Stiller
Research. Microsoft, Windows and MS/DOS are trademarks of
Microsoft corporation. IBM and OS/2 are trademarks of
International Business Machines Corporation. Vines is a trademark of
BANYAN Inc. NetWare is a trademark of Novell Inc. Unix is a
trademark of AT&T. Sidekick is a trademark of Borland
International.
Integrity Master (tm) - 3 - Version 2.22
Use of Integrity Master(tm) (also known as IM) requires acceptance of
the following license terms and warranty disclaimer.
L I C E N S E T E R M S
TO USE INTEGRITY MASTER, YOU MUST AGREE TO AND
UNDERSTAND THE FOLLOWING LICENSE TERMS AND WARRANTY
DISCLAIMER, OTHERWISE DO NOT USE THIS PROGRAM.
Each PC must have its own licensed copy. EACH COPY MAY
ONLY BE USED ON ONE PC. It may be removed from that PC
and installed on another PC but IT MAY NOT BE INSTALLED ON
MORE THAN ONE PC AT A TIME. To use Integrity Master on
more than one PC, you must license extra copies.
W A R R A N T Y D I S C L A I M E R:
INTEGRITY MASTER AND ALL ASSOCIATED PROGRAMS ARE
LICENSED "AS-IS". STILLER RESEARCH AND WOLFGANG STILLER
MAKE NO WARRANTIES, EITHER EXPRESSED OR IMPLIED, WITH
RESPECT TO THESE PROGRAMS, THEIR QUALITY, PERFORMANCE,
MERCHANTABILITY, OR FITNESS FOR ANY PARTICULAR PURPOSE.
IN PARTICULAR, INTEGRITY MASTER IS NOT GUARANTEED TO
PREVENT OR DETECT DAMAGE TO YOUR DATA OR PROGRAMS. IN
NO EVENT SHALL STILLER RESEARCH OR WOLFGANG STILLER BE
LIABLE FOR ANY CLAIMS FOR LOST PROFITS OR ANY DAMAGE,
INCLUDING BUT NOT LIMITED TO SPECIAL, INCIDENTAL,
CONSEQUENTIAL OR OTHER DAMAGE. SOME STATES DO NOT
ALLOW THE EXCLUSION OR LIMITATION OF INCIDENTAL OR
CONSEQUENTIAL DAMAGES, SO THE ABOVE LIMITATION OR
EXCLUSION MAY NOT APPLY TO YOU.
IF YOU USE INTEGRITY MASTER (IM), YOU ASSUME EXCLUSIVE
RESPONSIBILITY AND LIABILITY FOR ANY LOSS OR DAMAGE
DIRECTLY OR INDIRECTLY ARISING OUT OF THE USE OF THE
PROGRAM.
IN NO CASE SHALL STILLER RESEARCH'S OR WOLFGANG STILLER'S
LIABILITY EXCEED THE LICENSE FEES PAID FOR THE RIGHT TO USE
THE LICENSED SOFTWARE.
THE LICENSE AGREEMENT AND WARRANTY DISCLAIMER SHALL BE
CONSTRUED, INTERPRETED AND GOVERNED BY THE LAWS OF THE
STATE OF FLORIDA.
Integrity Master (tm) - 4 - Version 2.22
T A B L E O F C O N T E N T S
-----------------------------------
tm
PART ONE - Integrity Master User Guide
License and Warranty Terms ....................... 3
Chapter One - Why Integrity Master
Welcome! .................................... 7
Don't Read This ............................. 7
Why the User Guide .......................... 8
What Can Integrity Master Do? ............... 8
How Does Integrity Master Do These Things?... 9
What Makes Integrity Master Special?......... 9
Requirements and Limitations ............... 10
Chapter Two - Installing Integrity Master
Special Quick Install....................... 11
Full Installation........................... 11
Vital Files ................................ 12
Screen Colors .............................. 13
Using Integrity Master Menus................ 14
Chapter Three - Running Integrity Master
Integrity Master Screen Contents ........... 15
Initializing Integrity Data................. 15
What Is Integrity Data? .................... 16
The Check Menu ............................. 16
The Report File ............................ 18
System Sectors ............................. 19
Reloading ............................... 19
The Commands Menu .......................... 20
Disk Change and Directory Change ........ 20
Quit - Exit the Integrity Master ........ 20
Uninstall - Delete Integrity Data ....... 21
The Statistics Summary ..................... 21
Virus Checking Procedure ................... 22
Scanning for Viruses .................... 23
Scanning uploads ....................... 23
Detecting Viruses ....................... 23
Detecting Unknown (new) viruses ......... 24
The Integrity Master virus report ....... 25
False Alarms ............................ 26
Destroying Viruses ...................... 26
Data Corruption ......................... 27
Integrity Master and Disk Problems ........ 27
Integrity Master for PC Security ........... 28
Integrity Master for Change Control ........ 29
Command Line (BATCH) Execution ............. 30
Syntax .................................. 30
Error Levels ........................... 31
Using IMCHECK .............................. 31
Other Operating Systems .....................33
Microsoft Windows and OS/2............... 34
Networks ................................ 34
Integrity Master (tm) - 5 - Version 2.22
Chapter Four - Customizing
The Parameter (Options) File ................ 35
Options Menu ................................ 36
Options in SETUPIM .......................... 41
Integrity Data Options ...................... 42
Updating Your Hardware Configuration ........ 43
The Advanced Option Menu..................... 44
Chapter Five - Errors
Error Recovery .............................. 47
Solving Problems ............................ 47
Answers to Common Questions ................. 48
PART TWO - Data Integrity and Viruses
Chapter One - Threats to your data
Introduction - Viruses Get All The Glory .... 51
Hardware Problems............................ 52
Finger Checks ... ........................... 52
Malicious or Careless Damage................. 52
Software Problems ........................... 53
Software Attacks ............................ 53
Logic Bombs ............................. 53
Trojans ................................. 54
Worms ................................... 54
Viruses ................................. 54
General Virus Behavior................ 55
System Sector Viruses................. 57
Boot Sectors ...................... 57
Partition Sectors ................. 57
File Viruses ......................... 58
Miracle Infections ................ 59
How Many Viruses Are There?.................. 60
How Serious are Viruses?..................... 61
Chapter Two - Protection for your PC
"Fixing" your disk .......................... 63
Goof Protection ............................ 64
Intrusion Protection......................... 64
Virus Defenses ............................. 65
Scanners ................................. 65
Disinfectors ............................. 66
Interceptors ............................. 67
Inoculators .............................. 67
Integrity Checkers ....................... 68
Gadgets .................................. 70
Prevention................................ 70
Integrity Master (tm) - 6 - Version 2.22
Chapter Three - Virus Myths
Mythical Sources ............................ 71
Quick and Easy Cures ........................ 72
Silly Tricks ................................ 72
Certified Software? ......................... 72
Retail Software Only? ....................... 73
Write-Protecting Your Hard Disk ............. 73
Safe Computing (Safe Hex?)................... 74
Software Is Useless Against Viruses.......... 74
Chapter Four - Virus Realities
The ONLY Real Source of Viruses ............. 75
Shareware Is as Safe or Safer ............... 75
Few Virus Free Programs ..................... 76
Write-Protecting Floppies ................... 76
Beware the CE and the Demo! ................. 76
Chapter Five - What to do - Some Suggestions
Action is Vital - Now! ...................... 77
Backup Policy ............................... 77
Integrity Checking Policy ................... 78
Run CHKDSK .................................. 78
Determining Causes of Corruption ............ 79
Education ................................... 80
Signs of Software Problems ............... 80
Signs of Viruses ......................... 80
Responsibility .............................. 81
Policy and Routine .......................... 81
Networks and Viruses ........................ 81
Guidelines for Using Anti-virus Software..... 82
Chapter Six - Handling a virus attack
Don't Panic ................................. 83
Report the Attack ........................... 83
Play Detective............................... 83
Clean House (Steps to Remove the Virus)...... 84
Guard the House ............................. 84
INDEX ............................................ 85
Integrity Master (tm) - 7 - Version 2.22
tm
Part One - Integrity Master Users Guide
C H A P T E R O N E - I N T R O D U C T I O N
____________________________________________________________________
WELCOME!
Welcome to the family of Integrity Master(tm) users! Integrity Master
(also known as IM) is the fastest, most powerful data integrity and
anti-virus software available for any price. I hope that you'll find
Integrity Master an indispensable part of your PC tool kit. From now
on, you'll be back in control of all the data on your PC.
DON'T READ THIS!
Most people should never need to read the Integrity Master Users
Guide. If you're reading this to learn how to use Integrity Master,
you're here for the wrong reason. Just copy your files onto your
hard disk and execute SetupIM. The tutorial should tell you all you
need to know to get started. For additional help when using Integrity
Master (IM), just hit F1 and select the index. The odds are, what you
need to know is there.
While I think most people won't need to read Part One -
Integrity Master Users Guide (this part), I think everyone needs to
read chapters one through six of Part Two - Data Integrity and
Viruses. This will help you understand the different threats to your
PC and what you can do about them. You'll understand more clearly
how viruses work, how dangerous they are, and how to use Integrity
Master or other products to protect yourself.
Integrity Master (tm) - 8 - Version 2.22
WHY READ THE USERS GUIDE?
I've written this users guide for three reasons:
1) To provide more information on how to get the greatest benefit out
of Integrity Master. You'll learn how to:
o use IM to detect totally new viruses
o tell if file damage is likely due to a hardware problem or
possibly a virus or a trojan
o use IM to protect your PC from unauthorized tampering, etc.
2) To explain certain aspects of Integrity Master in more detail and in
different terms than the explanation available from IM's internal
help screens.
3) To satisfy people who prefer to read things on paper. If you prefer
to read things on paper, then you're here for the right reason.
Although, I'll bet the tutorial in SetupIM will surprise you. (Give
it a try!)
WHAT CAN INTEGRITY MASTER DO?
1) Detect and remove viruses. IM will even detect viruses that are
not known to exist at this point. For known viruses, IM will
recognize them by name and describe what they do.
2) Detect possible file corruption due to hardware or software
problems. This type of file damage is apparently at least 100
times more likely than virus infection, yet it usually goes
undetected.
3) Supplement or replace any PC security programs you have. IM
will inform you if anyone changes something on your PC's disk
while you were gone.
4) You just compressed your disk or you restored your files from a
backup. Are all the files really OK? IM will tell you.
5) You wanted to delete all your .BAK files, but you entered: "DEL
*.BAT" by mistake. Oops! IM will tell you exactly which files
you need to restore.
6) You need a change management system to keep track of growth on
your hard disk. Where is all that disk space going? IM will tell
you.
7) You're having problems with your disk drive. Your diagnostic
programs say all is OK . . . now. But were some files damaged
last night? IM tells you!
Integrity Master (tm) - 9 - Version 2.22
8) Your hard disk is having problems. DOS will not even recognize
it as a disk. IM can reload your partition and boot sectors to "fix"
your disk!
HOW DOES INTEGRITY MASTER DO ALL THESE THINGS?
1) It reads files as well as parts of the operating system on your disk
known as system sectors. The first time you use IM, you will run
an "initialize" that will read your disk and calculate cryptographic
signatures for each file and system sector. While it's doing this,
IM is also checking for signs of known viruses.
2) This signature data, along with other information such as the file
size, is encrypted and recorded in the "integrity data" file. IM
creates one such file for each directory on your disk.
3) On subsequent checks, the files and system sectors are read again
and the computed integrity data is compared with the prior values.
This allows IM to determine if anything has changed, even if the
time and date stamps reveal no change.
4) IM detects changes that a virus may make to associate itself
(companion and cluster viruses) with an existing program.
A virus can only infect your PC by associating itself with your
programs or system sectors. Each of these actions results in changes
to data on your disk. IM will detect these changes if a virus tries to
infect your system.
WHAT MAKES INTEGRITY MASTER SPECIAL?
1) Integrity Master is not just an anti-virus product but a complete
data integrity system. Viruses are but one threat to the integrity
of your PC. With Integrity Master you have a complete solution.
2) Unlike other integrity check programs, Integrity Master contains
extensive information regarding known viruses. If IM recognizes
part of a known virus, it will identify the specific virus and
provide specific steps to remove it (offering to do this
automatically) and check for possible damage. If it detects other
file changes that are characteristic of a virus, it will alert you to
that fact and provide appropriate instructions.
3) Unlike a virus scanner, Integrity Master allows you to detect
unknown as well as known viruses.
Integrity Master (tm) - 10 - Version 2.22
4) Unlike anti-virus products that merely find known viruses,
Integrity Master also detects files and sectors damaged (not just
infected!) by viruses.
5) Integrity Master is fast! We wrote it in 100% highly optimized
assembler language.
6) Integrity Master checks and protects areas on your disk known as
system sectors (the DOS boot and partition sectors), not just the
files. If these sectors become infected or damaged, Integrity
Master can quickly repair them.
7) Integrity Master utilizes easy to use menus with lots of help. You
don't have to fully understand some of the more complex areas of
data integrity, such as system sectors, yet you can be fully
protected.
8) The Integrity Advisor(tm) component of Integrity Master understands
special files important to DOS and will give you special advice,
with step by step instructions, if these files have changed.
INTEGRITY MASTER REQUIREMENTS AND LIMITATIONS:
o IM requires a PC with 255K of available memory and DOS 2 or
later. (At least 385 thousand free bytes are needed for maximum
speed.)
o IM supports super large disks and files.
o IM supports a maximum of 2621 files in a single directory.
o Do not use the DOS APPEND, SUBST or ASSIGN commands
together with IM. These can cause results that are misleading if
you don't carefully consider the effects of these commands.
Integrity Master (tm) - 11 - Version 2.22
CHAPTER TWO - INSTALLING INTEGRITY MASTER
____________________________________________________________________
SPECIAL QUICK INSTALL PROCEDURE
Since you may be wanting to do a quick evaluation of Integrity
Master to see how it meets your needs, we offer this short cut install
procedure. In contrast, the full install procedure is intended to guard
against unknown viruses already infecting your system or an attack by
a sophisticated user and is not necessary for an evaluation under
normal circumstances.
QUICK INSTALL:
1) Type "SETUPIM" and hit ENTER. Answer all the questions that
SetupIM will ask. SetupIM will prepare a customized full install
procedure for you and save it on a file. Rather than follow the
full procedure just continue with this quick install.
2) Simply copy your IM files, IM.EXE and IM.PRM, to a convenient
location. ("COPY IM.* A:" would copy them to a floppy)
3) Enter the command: "IM /IE /Dc" Substitute for "c", in the
"/Dc" parameter, the disk you wish to check. That's it!
The command line parameters (/IE, /Dc) are optional; to execute IM,
just enter "IM". The menus will guide you from there.
FULL INSTALLATION
1) Make sure your Integrity Master files are located somewhere other
than drive A. If they are on drive A, simply copy them to your
hard drive or a diskette that you can insert in one of the other
drives. Here's an example of how to copy the IM files to your
hard drive from the diskette in drive A:
C:
CD \
MD IMASTER
CD IMASTER
COPY A:*.*
Integrity Master (tm) - 12 - Version 2.22
2) Now, to begin the actual install process, type:
SETUPIM
Or, if you have an older (CGA type) LCD display, you may want
to enter:
SETUPIM /L
(most modern laptops work fine in color or monochrome mode
"/M")
If you have a two-color display on a color adapter, you may wish
to try:
SETUPIM /M
for a more readable display. SetupIM automatically senses the
type of video adapter you are using but the above two combinations
can fool it occasionally.
3) SetupIM will guide you from there. SetupIM will provide you a full
tutorial on using Integrity Master menus and give you an overview of
how Integrity Master works. SetupIM will then analyze your needs and
check out your hardware configuration. SetupIM's Integrity
Advisor(tm) component will customize IM's options so that it will
work best to meet your needs. The Integrity Advisor will also
prepare a custom designed procedure to finish the install and a plan
for day-to-day use of IM. In addition to displaying this plan on
your screen, the Integrity Advisor will write the plan to file
IMPROC.TXT. You can use your favorite utility to read IMPROC.TXT or
you can enter the command IMVIEW IMPROC.TXT to read it, or the
command IMPRINT IMPROC.TXT to print the file.
VITAL FILES
Please check file README.DOC for a full list of files that come
with Integrity Master and what's important about each file. To read
README.DOC, type: "IMVIEW README.DOC" and hit ENTER. If this file is
not present, don't use your copy of IM.
After you install Integrity Master, there will be only two files you
absolutely need to use Integrity Master:
IM.EXE - Integrity Master itself
IM.PRM - The parameter file which controls how IM works
- This file is created by SETUPIM.EXE
Integrity Master (tm) - 13 - Version 2.22
If you want to reinstall IM, or change advanced features of IM, you
will need:
SETUPIM.EXE The setup and install program (It creates
and updates IM.PRM)
When you install IM, SetupIM will create these files:
IMPROC.TXT Instructions on how finish installation and run IM
IM.PRM The parameter file (all option settings are stored
here)
SCREEN COLORS
IM normally automatically detects the type of video adapter you have
and uses appropriate colors for your equipment. There are two things
that can confuse IM:
1) Some programs change the DOS video mode from color to
monochrome or vice-versa. To correct this, just enter the
appropriate mode command (e.g., "MODE CO80")
2) Some equipment appears to have a different display than it really
has, such as an LCD display on a laptop.
If you find your display hard to read, you may want to override IM's
choice of video mode (colors). The best way to do this is to experiment
by using the command line parameters to specify an alternate set of
colors. Try each option and choose what looks the most pleasing.
Both IM and SetupIM accept these command line parameters:
/L - For older CGA liquid crystal displays (e.g., Toshiba 1000 laptops)
/M - Forces monochrome mode
/C - Forces color mode
/A - Forces automatic video detection mode (default).
Example: "IM /M" will use colors appropriate for a monochrome
display even if the display appears to be of a color display.
Once you've found the colors that work the best, it's usually best to
use SetupIM to select that video mode so that you don't have to remember
to enter the command line parameter.
Integrity Master (tm) - 14 - Version 2.22
USING INTEGRITY MASTER MENUS
Integrity Master (IM) and SetupIM both employ an advanced menu system.
When you first install using SetupIM, it will offer you an extensive
guided tour of how these menus work. This is the best way to learn how
to use the menus. Within Integrity Master, just hit F1 and select "Help
using the menus" from the help menu for assistance.
On most menus you will see one selection shown in a different color (or
underlined) than the other selections. The different color (highlight)
indicates that this is the chosen line. You can use the arrow (cursor)
keys to select any of the items on the menu. Each menu line has a
single capitalized letter showing in a different color. Pressing the key
matching that letter will also select that menu item. On many menus, an
extended explanation automatically appears as you select any menu line.
After you have chosen the appropriate menu item, you must hit the ENTER
key before anything will happen.
Integrity Master (tm) - 15 - Version 2.22
CHAPTER THREE - RUNNING INTEGRITY MASTER
____________________________________________________________________
INTEGRITY MASTER SCREEN CONTENTS
The top part of the Integrity Master screen tells you what options are
in effect and what IM is currently doing. The menus appear below this.
Be sure to go through the tutorial in SetupIM to learn how to use the
menus. When IM is busy checking your files, the report screen pops up
and replaces the lower half of the screen including the menu area.
The best way to get familiar with the information presented to you on
the IM screen is by hitting the F1 (help) key and selecting the
"Explanation of the display" entry. This will give you a step by step
guided tour of IM's display.
INITIALIZING INTEGRITY DATA
Before you can check your disk, you must initialize the integrity data
that describes the disk. You can use either the command line parameter
(/IE) or the Initialize menu within IM. Hit "I" or alt/I (hold down the
ALT key and press "I") to get to the Initialize menu.
.-----------------------------.----------.------------------------.
| Help Options Check |Initialize| ReLoad CoMmands |
.-------------------------- .-. .-------------------. ---.
| Entire disk integrity |
| Files on current Disk |
| Current and Lower directories |
| Current diRectory only |
| Boot sector |
| Partition sector |
| CMOS memory |
.--------------------------------.
From this menu, you create (initialize) the integrity data that describes
your files, CMOS and system sectors. While IM is initializing the
integrity data, it will (unless you turned virus checking off) check for
known viruses, and check for other indications of viruses or system
problems. For the system (boot and partition) sectors and CMOS, IM will
save reload information. This enables you to restore these (using the
ReLoad menu) if anything should ever infect or damage them. IM writes the
reload data to files CMOS.SRL, BOOT.SRL and PART.SRL for the CMOS, DOS
boot sector, and partition sectors respectively. Be sure to read the
section in Part Two, Chapter One, that explains why system sectors are
important.
Integrity Master (tm) - 15b - Version 2.22
CMOS MEMORY
CMOS is the special battery powered memory that contains information
on how your PC is configured. If this memory is changed, your PC may
be unable to boot so be sure to save the CMOS.SRL file on a floppy.
Generally, XT class (and earlier) PCs don't have CMOS memory. There's
usually a setup program (sometimes accessible only at boot time) that
allows you to change your PCs configuration and thereby change the CMOS
contents. If you do this be sure to use the CMOS option on the Initialize
menu to update IM's saved copy of your CMOS (in file CMOS.SRL).
CMOS is powered by a battery so that its contents will stay intact when
your PC is off. You must periodically replace this battery. When it
starts to fail, you will notice unexpected changes to your CMOS. After
you replace the battery, use the ReLoad menu to restore your original
configuration.
Integrity Master (tm) - 16 - Version 2.22
When you first use IM, please select "Entire disk integrity" initialize
to initialize the integrity data for all files and system sectors (the
boot or partition) that exist on the current disk. IM will also create
the system sector reload files (BOOT.SRL and PART.SRL). Be sure to save
a copy of these files on diskette to help you recover when your hard disk
fails. (Not all disks have both boot and partition sectors).
The other options on this menu correspond to matching options on the
CHECK menu.
WHAT IS INTEGRITY DATA?
When IM checks a file, it uses each byte of the file in a calculation to
compute cryptographic signatures for that file. A change to any part of
a file will result in a different signature. These signatures, along
with other significant information such as file size, are what I call
integrity data. IM writes an integrity data file for each directory on
your disk. These files can be stored with the files that they describe
or stored on separate diskettes.
When you first install, SetupIM chooses, at random, a unique algo-
rithm to compute the cryptographic signatures, and also chooses a
unique algorithm to encrypt your integrity data files.
WHAT ARE CRYPTOGRAPHIC SIGNATURES?
Just as your signature uniquely identifies you, the cryptographic
signatures serve to identify the contents of each file. If a virus or a
hardware problem changes a file, the signature computed for that file
will be different, although the file size and time and date stamps may
be the same. A change or the rearrangement of data in a file will result
in a different signature. When you execute SetupIM, it will randomly
select a unique algorithm for computing the cryptographic signatures.
THE CHECK MENU
From the Check menu, you can check files or system sectors for changes.
Use the up and down arrow keys to select the type of checking you'd like
to do. You may choose to check only specific things on your disk, such
as the system sectors or individual files, or you could check everything
on the entire disk. IM will report any added, deleted, or changed
files as well as any signs of viruses or other known problems. If
integrity checking is on, IM will read the files and check for any
changes. Use the Options menu to control whether full integrity
checking is on and the type of files to check. The fourth line at the
top of the screen shows the current status of integrity checking
including the type of files to be checked. If you
Integrity Master (tm) - 17 - Version 2.22
see: "Integrity check: On", this indicates that full checking will be
done on all files.
You can reach the Check menu by hitting "C" or alt/C.
.---------------------.-----.-------------------------------------.
| Help Options |Check| Initialize ReLoad CoMmands |
.----- .--------------. .----------.--------------------------.
| Entire disk integrity |
| Files on current Disk |
| Current and Lower directories |
| Current diRectory only |
| Specific file(s) |
| Boot sector |
| Partition sector |
| Disk for known Viruses |
| CMOS memory (FULL) |
.--------------------------------.
Entire disk integrity
Selecting this option and hitting the ENTER key will check any
system sectors (the boot or partition sectors) that exist on the
current disk for changes and then check all files in all directories.
Files on current Disk
Selecting this option and hitting the ENTER key will check only
files on the current disk. System sectors will not be checked.
Current and Lower directories
Selecting this option and hitting the ENTER key will check files in
the current directory and any files in any directories which are
defined descendant from the current directory. If the current
directory happens to be the root directory (e.g., C:\) then all files
on that disk will be checked since all other directories are
descendant from the root directory. Another example: if you're in
directory \DOS, directories such as \DOS\A, \DOS\UTILS or \DOS\A\B
would be checked in addition to \DOS.
Current diRectory only
Selecting this option and hitting the ENTER key will check only
files in the current directory.
Specific file(s)
Selecting this option and hitting the ENTER key allows you to
enter the name of a specific file to check.
Boot sector
Selecting this option and hitting the ENTER key will read the DOS
boot sector and check it for any changes. Please see the
explanation of system sectors later in this guide.
Integrity Master (tm) - 18 - Version 2.22
Partition sector
Selecting this option and hitting the ENTER key will read the
partition sector (also known as the master boot record) and check it
for any changes. Please see the explanation of system sectors later
in this guide.
Disk for known Viruses
The option to check "Disk for known Viruses" is intended only for
one-time quick virus scans or to do checks of all files (not just
those identified as executable files) for known viruses. You can do a
one-time quick virus scan on just the current directory or on the
entire disk. If you choose the entire disk, then the appropriate
system sectors will be checked as well as all executable files.
Checking all types of files is useful as a double check in the event
that IM detects an existing virus. This is suggested since it's
possible that you may have a program somewhere that uses a file with a
nonstandard extension to store executable code (e.g., overlays). If
you are aware of a program that uses extensions which IM does not
recognize as executable, then you may wish to use the Advanced menu in
SetupIM to add this extension to the list of extensions recognized by
IM. You generally won't need the virus scanning option except in these
special cases, since IM automatically checks for viruses during its
normal processing. You can also use the /VA, /VM, /VO, or /VR
command line parameters to perform a virus scan.
CMOS Memory
Integrity Master can check the CMOS memory describing the configuration
of your PC. It can check either the "FULL" or the "BASE" (the standard
64 byte AT CMOS portion) CMOS. The menu will display whether
"FULL" or base CMOS is being checked. You can use SetupIM to change
this. Most modern PCs now have more than the standard 64 byte base
CMOS memory. IM can check your entire CMOS. IM ignores the non-critical
or "known to change" portions of your CMOS when checking. CMOS is
used differently by each manufacturer, but IM will diagnose the
change to CMOS and report as much information as possible regarding
what has changed. For example, if you install a new floppy drive,
you would expect the CMOS describing the floppy setup to change.
If you see that many items in your CMOS have changed, then it's
a good bet that your battery is failing or a buggy program may have
trashed your entire CMOS. In this case, let IM reload your CMOS
for you.
IMPORTANT REMINDERS BEFORE CHECKING:
o Before using IM, be sure that you've run SetupIM (new install) and
followed the directions provided for you in file IMPROC.TXT.
o Before checking your files run an "Entire disk integrity" initialize.
o For protection against previously unknown viruses, be sure you
cold boot from a write-protected floppy before checking.
Integrity Master (tm) - 18b - Version 2.22
T H E R E P O R T F I L E
In addition to seeing a report of IM's findings on screen, you may wish
to save a report on disk or on paper. The Options menu in both IM and
SetupIM allows you to set the type of report (if any) IM will create. I
recommend that you allow IM to write its findings to an "auto-named"
disk file. By saving these report files, you can discover what changed
last April 1 or when you last changed a particular file. Each time you
run IM, it will write its findings to the end of the report file for
that day. For example, on June 1, 1994 the report would be on file
")(0601.REP". By saving the report files, you can maintain a complete
change history for your PC. If you ever want to find out what happened
to a file, the full history will be
Integrity Master (tm) - 19 - Version 2.22
available. If you wish to keep more than one year of history on-line,
try copying all the report files (COPY *.REP) to another disk or
subdirectory.
If you choose an "auto-named" report file, you can elect that IM place
the file in the root directory of whatever disk is being checked or you
may choose to place it on a specific disk of your choice. You can also
give the report file absolutely any name you wish. If you choose a
specific filename, you may include the disk and directory as part of the
filename. If you do not specify a disk or directory as part of the
filename, then IM will create this file in the current directory at the
time you execute IM.
If you elect printed output, IM will ask you to choose LPT1, 2, or 3.
In the rare event that this does not work with your printer, you may
also print by asking IM to write the report to a specific file name such
as "PRN" (the printer). If you use "PRN", you will get less
sophisticated error handling and messages since DOS drives the
printer rather than IM.
S Y S T E M S E C T O R S
System sectors are special areas on your disk containing programs
that are executed when you boot your computer. These sectors are
invisible to normal programs but are vital for correct operation of
your PC. They are a common target for viruses. Please read the
detailed description of Boot and Partition sectors in Chapter one of
PART TWO - Data Integrity and Viruses.
R E L O A D I N G
You can reach the ReLoad menu by hitting "L" or alt/L from any of
the other primary IM menus.
.-------------------------------------------.------.--------------.
| Help Options Check Initialize |ReLoad| CoMmands |
.---------------------------------------- .-. .------------. .
| Boot sector |
| Partition sector |
| Missing partition |
| CMOS memory |
.---------------------.
From the ReLoad menu, you may reload your CMOS memory, DOS boot sector or
your partition sector (master boot record), in the event that they have
become damaged or infected with a virus. The "reload Missing partition"
option must be used if you have a disk so badly damaged that DOS will not
recognize that the disk exists. You will then be prompted to identify the
disk on which to reload. You can identify it either by the logical disk
letter (A-Z) or by the physical device number (0 for the first physical
hard drive, 1 for the second and so on). If the disk you are about to
reload is not the same disk from
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which the reload data was saved, IM will warn you, but will give you
the option to continue with the reload. You can take advantage of this
if you need to reload the boot sector of multiple floppy diskettes:
o Locate a clean diskette of the type that is infected
o Initialize integrity data for the boot sector of that floppy.
o Make sure that the BOOT.SRL file you just created is the only one
IM can find. (Temporarily move any other .SRL files)
o Turn the report file off
o Change to the drive containing an infected floppy (CoMmands
menu).
o Tell IM to reload the boot sector.
o Insert and another diskette and keep reloading. IM will locate the
BOOT.SRL file on one of your other disks and reload the sectors
on each floppy diskette.
The Commands Menu
You can reach the "CoMmands menu" by hitting "M" or alt/M from
any of the other primary IM menus.
.----------------------------------------------------.--------.---.
| Help Options Check Initialize ReLoad |CoMmands| |
.------------------------ .--------------------------. .-. .
| Temporarily Shell out to DOS |
| Quit - exit the Integrity Master |
| Disk change |
| DiRectory change |
| Uninstall - delete integrity data |
.-------------------------------------.
Temporarily Shell out to DOS
This allows you to exit IM to the DOS prompt, but leaves Integrity
Master loaded in memory so you can quickly return by using the
Exit command. Shelling allows you to exit IM, and execute most
other programs at the DOS prompt (such as copying files or
formatting disks).
Disk Change and DiRectory Change
You'll mostly use this menu to change the current disk or
directory. (You can also use the "/D" command line option to
change to one or more other disks or use the "/P" command line
parameter to start in a different directory)
Quit - exit the Integrity Master
In addition to using the "Quit - exit the Integrity Master" option on
the CoMmands menu, you can use the ESCape and alt/X keys to
terminate IM from any point. The ESCape key allows you to
Integrity Master (tm) - 21 - Version 2.22
terminate most IM menus without taking any action and return to
the prior menu. The only exceptions to this are menus which
require a response one way or the other. These are usually the
result of a detected error of some type. If you hit ESCape enough
times, IM will ask if you really want to quit. You must select
"Yes" and hit enter to exit. The fastest way to exit IM, is by hit-
ting alt/X (hold the ALTernate key down and hit the "X" key).
This allows you to quickly exit without the final "Do you really want
to quit?" prompt.
Uninstall - delete integrity data
If you have integrity data files in each directory of your hard disk,
you can quickly delete these files by selecting Uninstall on the
CoMmands menu. If your integrity data is stored on a different
disk than the files it describes (such as a floppy) then this option
will have no effect.
THE STATISTICS SUMMARY
Whenever you finish checking files, IM will show you a summary of its
findings. Since the summary contains a time and date stamp, you can use
the report file as a chronological log of all changes on your PC even if
you have it going to the printer. The summary shows statistics for all
file changes as well as system sector and memory checking. IM reports
the number of times it checked a file's integrity data against the DOS
directory information, as "files processed". It also reports a separate
count of the number of files actually read and checked. IM resets all
statistics (with the exception of the memory check results) each time
after it displays the summary statistics. This means that on subsequent
file checks, the system sectors will be indicated as "Not checked" even
though they were indicated as checked on the prior display. Why is
this? IM does this because some disks are removable and disk X may
suddenly be a different disk. IM shows the statistics for any viruses,
suspicious files, or system corruption (which includes file open and
read errors) in red.
VIRUSES - WHAT ARE THEY?
Viruses are but one of many threats to your data. You are far less
likely to be hurt by a virus than the other causes of data damage such
as software conflicts and general glitches of various types.
Viruses are programs that attach themselves to other programs in such a
way that when the other program is executed, the virus code will also
execute. The infected program usually appears to execute normally but
the virus may be attaching itself to additional programs each time the
infected program runs. Many viruses are triggered by some event (such
as a particular time or date) into an attack phase,
Integrity Master (tm) - 22 - Version 2.22
resulting in anything from music to serious file damage. Viruses
often wait a long time before attacking; their goal is to spread as far
as possible before revealing their presence. Some viruses go resident
in your PC's memory, taking over your PC. This enables them to infect
at will and elude detection attempts.
A virus may attach itself to programs in two ways that many people
are not aware of. The first way is to infect the programs that are in
the system (boot and partition) sectors of your PC. The second way is
by changing system information on your PC so that the virus code is
executed before the intended program. The most obvious way to do this
depends on the fact that if both a .COM and .EXE file have the same
name, DOS will execute the .COM file instead of the .EXE file. Such a
virus is commonly called a companion or spawning virus. These viruses
locate .EXE files and then plant themselves as .COM files of the same
name. The virus (the .COM file) can execute, spread further, and then
run the .EXE program so that everything appears normal. (Don't worry; IM
detects all types of viruses!) Please read PART TWO Data Integrity and
Viruses to learn more about viruses.
VIRUS CHECKING PROCEDURE
When you install Integrity Master using SetupIM, the Integrity Advisor
will prepare a complete procedure for running IM. If you indicated that
you wanted to detect viruses, then this procedure would include the
steps you need to check for viruses. This step by step procedure is
customized to your own preferences, so be sure to read file IMPROC.TXT
first.
To be certain of detecting even unknown viruses, it is vital to cold
boot from your write-protected floppy containing IM before checking for
viruses. Do NOT use Ctrl/alt/del to boot, but turn your PC off and then
on. Some PCs have a reset button that will force a cold boot.
Whenever you engage in any activity that changes or rearranges many
files, run at least a "Quick update", so that your integrity data
accurately reflects the status of your PC. Use the Options menu to
change the type of integrity checking.
o With Integrity "CHECK ON", do a full integrity check (rather than
a "quick update") of all files at least once a month to detect any
unexpected changes.
o If your work exposes you to programs that may be infected with viruses,
do a daily full check of your disk for any unauthorized changes. To
save time, use the Options menu to limit checking to executable
programs. Check at least the current directory if you have executed
any new or "strange" programs.
Integrity Master (tm) - 23 - Version 2.22
o After installing any new software, IMMEDIATELY run IM to
initialize the integrity data for the new files you have created. Be
sure that you save a write-protected disk containing a copy of the
software. It is vital that you do this before you start to use the
software.
o It is critical to do extra checking any time you copy programs (e.g.,
*.EXE or *.COM files). When you copy programs, be sure to copy your
integrity data also. For example, if you are doing something like a
"COPY *.EXE D:\DOS", then also enter a command to copy the integrity
data to "D:\DOS". (If you're not sure what the names of your integrity
data files are, check your IMPROC.TXT file or select "Integrity data
options" on the SetupIM Change menu.) If you simply copy all files
(COPY *.*), then you won't have to worry; the integrity data will
automatically be copied along with the programs. Afterwards, run IM to
check that the files were copied without damage or virus infection.
Naturally, IM will report any files that weren't copied as deleted when
you run this check.
SCANNING FOR VIRUSES
To quickly do nothing but scan one or more disks for known viruses:
o Use the CoMmands menu or the "/Dx" command line parameter to change to
the drive you want to scan. (do not use a colon (":") with the "x".)
o Use the Options menu to turn the report off or to set the report to
go to the printer or your hard disk.
o From the Check menu choose "Disk for known Viruses". Hit ENTER and
select either "One-time screening" or (if you're planning to check
several floppies) "Check Multiple diskettes".
o This scans the first disk. When you see the display summarizing the
results of the scan, insert the next diskette and hit enter to scan that
diskette or hit ESCape if you're done scanning.
IM will return a DOS error level of 64 or greater if it encounters a
known virus so you an use IM in a batch file which checks for viruses.
You can also use the command "IM /Dx /VM" to scan multiple diskettes
in drive x. Use "/VO" rather than "/VM" to scan only one diskette.
SCANNING BBS UPLOADS
You can use IM to scan uploads to your BBS. The command
IM /VR /NE /b
will scan the current directory or
IM /VR /NE /b /Pxxxx
will scan the directory (and/or disk) specified by xxxxxx.
If your upload processor provides a filespec like "*.*" or "*.COM",
you do not need to feed it to IM on the command line. However if it does,
you can include it as the first parameter. (e.g. "IM @FILES@ /B /VR /NE").
IM returns an ERRORLEVEL of 64 or greater if it finds a virus.
To scan a disk for known viruses AND to get data integrity protection:
o Use the Options menu and set the "Files to iNitialize" option to
"Executable programs."
o Use the Initialize menu to initialize "Entire disk integrity".
The command line options: /VA, /VM, /VO, /VL, and /VR are available for
scanning. Remember that virus scanning will detect only viruses known
at the time this program was written. As with any scan program, you
should have the latest version if you intend to rely upon scanning for
serious protection.
DETECTING VIRUSES
o Make sure that you specified that you wanted virus protection when
you installed IM. If you didn't, then run SetupIM and select
"Reinstall".
o Make sure you carefully followed SetupIM's instructions in
IMPROC.TXT.
o If a virus is found on your PC, IM will almost always recognize it
by name and explain how to remove it. IM will also advise if viral
signs are present on changes that don't match known viruses.
Integrity Master (tm) - 24 - Version 2.22
o Whenever IM reports a change to an executable program, it's important
to discover the cause. Some programs modify themselves when you change
their options; some programs change themselves every time they run.
Changes to executable programs are indicated in red on the report
screen and are bracketed by "...." to make these changes obvious.
o If only a single program has changed and IM does not reveal this to be
corruption, then you probably do NOT have a virus. If you have any
doubt that a program change may be a virus, be very careful and run
full checks with IM after executing this program. (Cold boot (power off
and on) from a floppy before running IM) Any program changes detected
at this point indicate a virus. Please report this (see file
VIRREP.DOC for complete details).
o For speed, use the Options menu to limit checking to executable files.
DETECTING UNKNOWN (NEW) VIRUSES
IM has the capability to detect infection by an unknown (new) virus
as well as the ability to identify known viruses and their
characteristics. If IM detects an unknown virus, it clearly can't
provide the detailed information that it provides when it detects a
known virus. Because of some of the generic detection techniques used
in IM, there's a good chance that it will identify and describe a new
virus. How is this possible? This is only possible if the virus is not
totally new but a modification of an existing virus. In this case, IM
may identify the "new" virus as a virus it knows about because someone
created the new virus by simply making some changes to an existing
virus. (Most "new" viruses are created in exactly this way.) IM will
usually notice the code from the old virus still present in the new
virus and identify it in this way.
What about totally new viruses? These are a little more work to
identify. In this case, IM will inform you that it has detected a
change in a file or a system sector, but won't announce that a virus is
present, unless it's similar to a known virus.
How do we decide whether a virus is responsible for the detected
change? Consider the following factors:
o Has IM identified virus-like symptoms with this change? Such
symptoms include an unusual value in the DOS time or date stamp,
and file corruption detected (no change to the time and date stamp
but a change to the file).
o Are numerous unrelated executable files changed?
If the answer to one or both of these questions is "yes" then it's time
to do some more checking to see if it's really a virus. Please read the
Integrity Master (tm) - 25 - Version 2.22
section on Virus Signs and Playing Detective in Part Two - Data
Integrity and Viruses. Following these procedures will let you
determine if you have encountered a brand new virus (lucky you!). If
you have encountered a virus, or you are not sure, please contact us;
see file VIRREP.DOC for details on reporting viruses.
THE INTEGRITY MASTER VIRUS REPORT
When IM detects a known virus it will optionally present at least one
full screen of information. The virus report screen gives you the
following information:
o The name of the virus. This is usually the name used by the UK's Virus
Bulletin but in some cases we use an abbreviated or more common name.
This name corresponds to an entry in file VTEXT.DOC. Many viruses have
been built as modifications to existing viruses. By identifying common
(hard to change) code elements in the base virus, IM can identify
multiple viruses by spotting their common characteristics. This means
for example that if IM reports the Jerusalem virus, it could also be
the Anarkia, Anarkia-B or the Payday virus. Since viruses go by many
names, alternate names for the same virus are listed in this table too.
o IM lists the type of files or system sectors infected by this virus.
o If the virus is known to seriously interfere with normal operation of
your PC, this is mentioned. We don't classify messages, bouncing balls,
or music as serious interference. We do consider slowing execution of
your PC or halting the system as serious.
o IM will mention if the virus is known to either deliberately or
inadvertently damage data on your disk. Beware, though, some idiot
could, at any point in time, modify a previously harmless viruses to do
something destructive. An example of this is the Cascade virus
(letters cascade down on your screen when this virus activates). The
first version of this virus was harmless but someone created a variant
that will format your disk. In this case, IM makes a special check for
the dangerous variant of the virus and warns you if it's detected. In
spite of this, please, NEVER assume that a virus is harmless. If we
don't mention that a virus is known to damage files, it means only that
no one has reported damage from this virus. Be careful; you may have a
variant of the virus that might very well be dangerous!
o IM presents step by step removal instructions for the virus.
Sometimes IM presents additional screens describing necessary or suggested
actions. This is true if the virus is detected in memory. When IM first
starts, it checks the memory of the PC for presence of known viruses
(unless you deactivate this check using SetupIM or the "/B" (bypass)
Integrity Master (tm) - 26 - Version 2.22
command line parameter); if IM detects a virus, it will ask you to
immediately cold boot your PC. Checking further at this point could be
very dangerous since it might spread the virus. Other special viruses
such as companion or cluster viruses (see PART TWO for details) will
generate an extra screen identifying that specific virus and mentioning
alternate ways to remove the virus.
FALSE ALARMS
If IM announces detection of a known virus, could this be a false alarm
(not really a virus)? If IM has checked this file before or if it has
found more than one file infected, then you very likely have a REAL
VIRUS! If this is the first time that IM checked this file, and if it
found only one file infected after checking your entire disk, then it's
probably a false alarm. Although it is very unlikely, it IS possible
that a legitimate program could contain code that matches a virus.
IF YOU THINK YOU HAVE A FALSE ALARM, PLEASE NOTIFY STILLER RESEARCH.
WE WILL DETERMINE IF A VIRUS IS PRESENT; IF IT IS A FALSE ALARM, WE
WILL, IF POSSIBLE, SEND A CORRECTED VERSION OF IM.
Some anti-virus programs contain unencrypted virus fragments that IM may
detect. It's usually safe to assume these programs are not infected.
Some of these programs also leave virus fragments in memory that IM may
then detect and announce as a memory resident virus. Please do not take
any chances in such a case and follow IM's instructions to cold boot,
even though it's likely to be a false alarm.
If you have just read an infected disk or a file, there is a chance that
IM may detect a piece of this file in memory and announce a resident
virus when one really isn't resident. In such cases, it's best to play it
safe and cold boot from a write-protected diskette.
DESTROYING VIRUSES
If IM detects a known virus, it will display the steps to remove the
virus and offer to remove it automatically.
If IM detects program or system sector changes that may be due to a
virus, please follow these steps:
o Save at least one infected diskette or file and report this to us. This
will allow us update IM to recognize this virus and hopefully track
down the source of the virus! See file VIRREP.DOC for complete
details.
o Cold boot your PC (power off and on) from a write-protected
floppy disk.
Integrity Master (tm) - 27 - Version 2.22
o Run an "Entire disk integrity" check, noting any changed programs
or other possible damage by the virus.
o You can allow IM to remove the virus or follow its directions to
remove the virus manually. Restore infected files from the original
program diskettes if possible.
o Reload your system sectors if they were damaged.
o Restore any damaged files or programs from the original diskettes
if possible.
o Very carefully, check any floppies you've used.
o Run an "Entire disk integrity" check daily for a while.
DATA CORRUPTION
If a program changes a file by normal means, the file's time and date
stamp will be updated to reflect this change. On the other hand, if a
virus or a hardware or software problem causes a file to be changed,
there is often no change to file's time and date stamps. IM calls this
file corruption and raises a special alarm if it detects this. If you
find a corrupted file, the odds are it's NOT a virus. The most likely
cause of corrupted files is software conflicts. The next most common
cause is hardware problems. In any case, if you have a corrupted file,
it's essential you find what the cause is. In Part Two - Data Integrity
and Viruses", I have a chapter titled Determining the Cause of Data
Corruption. Please read that chapter very carefully when (not if!) you
detect a corrupted file. The next section describes using IM when you
are having suspected disk hardware problems.
INTEGRITY MASTER AND DISK PROBLEMS
It's an unfortunate fact of life that all disk drives will eventually
fail; sometimes at the worst possible moment! Before disk drives
totally fail, they usually start exhibiting signs of problems, such as
inability to reliably read and write certain areas on the disk.
Unfortunately, these failures tend to be intermittent. The result may be
that you have damaged files, but when you run your disk diagnostic
software, no problems are found. By using IM to do periodic full
checks, you can detect these problems when they first begin and prevent
more major disk problems, such as total failure, from taking you by
surprise. If you have an MFM, RLL, or ESDI type of disk drive you
probably can extend its life slightly by doing a low level format, or
using a product such as Steve Gibson's SpinRite(R) that can do a
nondestructive low level format. The key here is to detect disk
problems early before any serious damage is done.
Integrity Master (tm) - 28 - Version 2.22
IM replaces the DOS critical error handler with its own more advanced
routine. If a disk error occurs, you will see a warning screen
explaining what has happened, rather than the dreaded "Abort, retry, or
fail" message that DOS provides. IM may also present a menu offering
you additional options (depending upon the type of error and the
circumstances) such as repeating (retrying) the operation.
If an error occurs while IM is checking files, it will report either
"Read fail" or "Open fail" in place of the normal signature data on its
report:
Name and Signature File Update Update
Status: Type: Extension: Val1: Val2: Size: Date: Time:
------- -------- ---------- ---- ---- ---------- -------- --------
Added File NORMAL EXE 0D83 4E93 2048 11/05/92 14:00:56
Added File DISKERR EXE Read fail 140792 11/05/92 14:01:02
Added File CANTOPN FIL Open fail 123 10/05/91 10:11:20
In addition to "Read fail" or "Open fail" appearing in the IM report,
additional information regarding the type of error will also appear and
be recorded in the report file (or printout) as well in the on screen
report.
Whenever IM encounters an error reading a file, it will NOT replace the
original integrity data with the current (in error) data. This means
that if you have a read error on a file, and you either "fix" the file
using some utility or restore the file from a backup, you can then run a
check on that file and know whether or not your file was correctly
restored.
If you run IM in an environment where more than one program can have a
file open, you may get an "Open fail" or "IO error" due to another
program having this file open. This can happen on networks (LANs), with
OS/2, or with windows. When this error occurs, you will see a detailed
explanation along with a menu offering several options. I recommend you
select the option to ignore any further open errors; this way you will
still see detailed information on any other problems discovered by IM.
You can avoid this error display and most others by using the "/NE"
command line parameter (pause on emergencies only).
INTEGRITY MASTER FOR PC SECURITY
Although there are no 100 percent reliable techniques to prevent
someone from making unauthorized changes to your data while you
are away, IM does offer a 100 percent reliable way of detecting these
changes.
If you specified that security was important when you first executed
Integrity Master (tm) - 29 - Version 2.22
SetupIM, its Integrity Advisor will make recommendations on how to use
IM to get the level of protection you need. It saves these
recommendations on file IMPROC.TXT. By storing your integrity data on
diskettes and keeping these diskettes in a safe location, you can detect
any changes that occur on your PC. This should provide you protection
even against a user who understands how IM works and is technically
adept. For most situations this is probably overkill!
Keeping the integrity data on diskette may provide more protection than
you need. Simply keeping your parameter file (IM.PRM) on a diskette
will provide a very high level of protection. Since a user breaking
into your PC will not be able to tell how the integrity data is
computed, this user will not be able to change a file and then adjust
the integrity data to hide the changes, even if they have a copy of the
IM program. This provides almost as much protection as keeping the
integrity data on diskettes.
If you keep the parameter file on the same disk with the files you
check, it's possible that someone could modify your files and then run
IM to update the integrity data, in this way covering their tracks. This
person would obviously have to have enough knowledge about your PC to
know that you use IM. If you'd like to keep your parameter file on the
diskette with your files you can still achieve a high degree of security
by renaming IM.PRM and locating it in an unlikely directory. When you
invoke IM you will have to specify the name of the directory and the new
name for the parameter file. For example, the command: "IM
D:\DOS\UTILS\BORING.DAT" will read the IM parameter information from
file BORING.DAT in directory \DOS\UTILS on disk D.
INTEGRITY MASTER FOR CHANGE CONTROL
To use IM for change management, you really don't need to use integrity
checking. Simply running IM, in "Quick Update" mode, (which does not
actually read files unless the DOS time/date stamp or file size have
changed), is adequate to provide change management. "Quick update" mode
only requires about 10 seconds to check about 270 megabytes (8000
files). To keep a full record of what has changed on your PC, I
recommend you use "auto-named" report files and that you keep all your
report files. At the end of the year, you may wish to copy all the old
report files into a directory for that year. For example, on January 1,
1993:
CD \
MD REP93
COPY *.REP \REP93
DEL *.REP
This creates a directory called "\REP93", copies all report files to
that directory and then deletes the old report file.
By following this procedure you have a complete record of all changes on
your PC. If you want to know when a particular file last changed, it's
easy to search through the report files for that filename. If you want
to know where all your disk space is going, you can go back and see
which files were added or which files grew.
Integrity Master (tm) - 30 - Version 2.22
COMMAND LINE EXECUTION
Integrity Master is really designed to work by use of its menus.
However, most functions can be automatically invoked from the
command line to allow you to start IM from batch files.
SYNTAX FOR IM COMMAND LINE:
IM Fspec /A /B /C /Cx /Dxyz /F /H /Ix /L /M /Nx /NOB /Ppath /Q /Rx /REPA
/RF=filespec /Vx /1
FSpec optionally specifies the name of the parameter file to be used. It's
best to specify the disk and directory path as part of the filespec.
For example: use "IM C:\dos\NEW.PRM" rather than "IM NEW.PRM".
If you don't use this option, IM will search for file IM.PRM.
"/Dxyz" change to disk "x", process and then change to disk "y", etc.
If used with more than one disk, this should be used with one of the
"/Cx", "/Ix" or "/Vx" parameters.
"/Ppath" change to directory (and optionally disk). If you specify a disk
disk here don't also use "/Dxyz". (e.g. "/P\dos" or "/Pc:\dos")
"/1" Only "1 line" virus reports. Turns off the detailed virus descriptions
"/B" bypass memory check
"/F" Forces full integrity checking if quick update is set as the default.
"/H" (or /?) produces this help display
"/NOB" No Beep. Disables sound.
"/N" Nonstop: the same as setting "Halt" to "Serious problems" on the
Options menu. IM will stop only on viruses or serious problems.
"/NE" Stop on Emergencies only. This almost never stops.
"/Q" Forces IM to run in "Quick update" mode.
"/REPA" Report all. When scanning, IM lists all files scanned for viruses
When initializing, IM lists all files on the report file.
"/RF=filespec" writes the report to "filespec" (can include disk + path).
-------------------------------------------------------------------------------
The following may be used to override video mode selected during install:
"/A" Auto adjust of video mode. "/L" Use for older LCD displays
"/C" Force use of full color mode. "/M" Use monochrome colors.
-------------------------------------------------------------------------------
/Cx values: do type "x" integrity check and then quit:
"/CE" Check Entire disk integrity. "/CB" Check boot sector.
"/CD" Check all files on DOS disk. "/CP" Check partition sector.
"/CR" Check files in this diRectory. "/CF=filespec" Check this one file.
"/CL" Check this + lower directories "/CC" Check CMOS memory
(REMINDER: Scanning by itself is not sufficient protection against viruses!)
------------------------------------------------------------------------------
Integrity Master (tm) - 31 - Version 2.22
/Vx options scan system sectors and files for signs of known viruses:
"/VA" Check ALL files on a disk (not just executables).
"/VM" Scan multiple diskettes with only one key press between diskettes.
"/VO" One-time virus scan of programs on current disk.
"/VR" One-time virus scan of programs in current directory.
"/VL" One-time virus scan of current directory and all lower directories.
-------------------------------------------------------------------------------
/Rx values will reload one of the system sectors on the current disk and quit.
"/RP" Reload Partition sector "/RB" Reload DOS Boot sector
Ordinarily, you don't need ANY parameters. Just enter: "IM". IM is menu
driven with lots of on-line help. The command line parameters most often
used for automatic unattended integrity checking. If you don't have
"HALT" set to "Serious problems" or "Emergencies only" (on the Options
menu), use "/N" (or "/NE") to avoid pausing for input. If you wish to
have IM automatically locate your parameter file, DO NOT specify it on
the command line. If you specify it on the command line and it is not
located in the current directory, then you must include the drive and
directory of the parameter file along with the name.
Examples:
"IM /L /CE /DEF" -Uses colors appropriate for older CGA type LCD displays.
Checks the system sectors as well as all files on disk E
then changes to disk F and repeates the check there.
"IM /IR" Creates new integrity data for files in this diRectory.
"IM /CF=A:\X\IO.SYS" Checks the file IO.SYS in directory \X on
disk A:.
"IM D:\IO\X.PRM /CD" Checks all files in the current disk using options
saved in the parameter file "X.PRM" located in "D:\IO".
"IM /RB /DA" Reloads the DOS boot sector on disk A.
To execute IM automatically in unattended (batch) mode, do the
following:
o Use the Options menu to activate the report file. Save this change
by selecting the first option on the Options menu, "Write option
changes to disk."
o Either set the halt options to "Serious problems" (on the Options
menu) or use the "/N" command line parameter ("IM /N").
Remember that you can use multiple parameter files if you don't
want your options always set to nonstop.
o Prepare the IM control card to do the type of checking that you
want. For example: "IM /N /DG /CE" will run nonstop on disk G:
and check the entire disk (/CE), including system sectors.
o If you have a timed execution program, such as the one available
with PCtools, you may want to have it invoke IM or add IM to any
batch file that you run regularly, such as nightly backup batch file.
Integrity Master (tm) - 32 - Version 2.22
ERROR LEVELS
Integrity Master returns the following DOS error levels. You can check
for these error levels in a batch file and execute your own special
procedures depending upon IM's findings. One of our beta testers has
their PCs automatically phone their help desk if an error level 24 or
greater is encountered.
00 Processing complete with no changes detected
08 Checking complete with added or deleted files detected
12 Checking complete with changed files detected
16 Checking complete with changed programs detected
24 Checking complete with suspicious file changes detected
32 Checking complete but a file or system sector showed signs of
corruption or an I/O error. This will be in addition to any of the
lower valued indicators such as change to a program. So if a
program changed, the error level would be 16 + 32 = 48.
64 One or more viruses were detected. Any of the lower status
indicators will be included with this one.
128 If a vital IM file is determined to be missing or damaged
192 A fatal error occurred during execution, such as not enough
memory or a disk error in internal processing.
200 Control card error (an error in IM's "/" parameters).
Using IMCHECK
IMCHECK.EXE is a fast stand-alone file checker. It will read
whatever files you specify and compute signature data similar to what
Integrity Master uses as part of its integrity data.
If you print the IMPROC.TXT file created by SetupIM, you will see
the check values that IMCHECK should report for IM.EXE and
IMCHECK itself.
Syntax is: IMCHECK [d:] [path] filename [/N]
"filename" specifies the files to check. Wild card characters such
as * or ? may be used.
"/N" Display dates in US numeric MM/DD/YYYY format.
Entering IMCHECK with no parameters will display an explanation
of how to use IMCHECK.
For example: IMCHECK D:\DOS\TEST.* would check all files in
the DOS directory on disk D: that begin with TEST but with any file
extension.
Integrity Master (tm) - 33 - Version 2.22
IMCHECK can be very handy when you send files to others and you
want to make sure that they got a good copy of your files. Simply
run IMCHECK on your files. You will see a report like:
IMCHECK 1.4 - Integrity Master (TM) standalone file checker.
Copyright 1990-1993 by Wolfgang Stiller - all rights reserved.
Checking: MYFILE*.*
File Name + Check Check File Update Update
Extension: Val1: Val2: Size: Date: Time:
---------- ---- ---- ------- --------- ------
MYFILE.001 DA37 1612 4512 9-Jun-1992 7:44:30
MYFILE2.DAT 46F7 4F41 277 10-Feb-1993 16:47:58
Total======> B518 56D9
Record the check values and make sure the other person runs IMCHECK
to compare the check values. The "Total=====>" values will match
only if the files are checked in the same order.
SPECIAL LICENSE TERMS FOR IMCHECK:
When you purchase your copy of Integrity Master, you will get permission
distribute copies of IMcheck to anyone with whom you share files so they
can verify the integrity of these files.
When you register, besides all the other benefits, you will get the
advanced version 2 of IMcheck that provides multiple check algorithms,
dirrectory checking, and more detailed file diagnostics.
ONLY registered (licensed) IM users may distribute IMcheck.
OTHER OPERATING SYSTEMS
Although Integrity Master is designed to run in the DOS environment
on Intel 80x86 family microprocessors, it is useful with other
operating systems and processors such as OS/2, Unix, MicroSoft
Windows and various Network (LAN) operating systems such as
Netware and VINES. You can even use it on a Macintosh with DOS
emulation. On most of these non-DOS systems you can't check the
system sectors in the same way as under DOS since the underlying
operating system support is different. Since these operating systems
are multitasking, Integrity Master may find that it can't read certain
files that are in use by the operating system. This is normal and will
not interfere with a full system check. There's more information on
this in the section on Integrity Master and Disk Problems.
While, it may be most convenient to do most of your checking under
your normal operating system, I strongly suggest that you prepare a
DOS boot check and occasionally check under native DOS. This is
currently the only way to give your system the most secure checking
possible.
Integrity Master (tm) - 34 - Version 2.22
Microsoft Windows and OS/2
Integrity Master will run quite happily under Windows or OS/2 as a
DOS application. You can even run IM in the background while you
use a different application. However, this will probably prevent it
from checking whatever files that you are currently using.
If you are using a non-DOS file system such as the "High
Performance File System" (HPFS) under OS/2, Integrity Master will
be able to check only those files that DOS can access. For OS/2
HPFS this means that files with more than eight characters in the file
name or more than three characters in the extension cannot be
checked. For example, IM could check file 12345678.ABC but not
file 123456789.ABC.D under HPFS.
Networks
Please read file NET.DOC (use "IMVIEW IM.DOC) to learn about some
very effective ways to install IM on a LAN. If you have a local area
network (LAN), you can use Integrity Master on both the file server
and the workstations. IM can be used on a network by running it on
the separate workstations as well as on the server. It can be
configured in different ways. If you place IM.EXE on a shared disk
available to all workstations, you can have separate parameter
(IM.PRM) files for each workstation or you could have a central
IM.PRM in the directory with the shared IM.EXE. It is more secure to
allow each workstation to have its own IM.PRM, but using a common
file makes it easier to copy or move files and then immediately check
to make sure the files are intact. If the server does not run DOS,
then you will need to check the files on the server from one of the
DOS workstations. Part Two contains a section titled Networks and
Viruses that provides some general procedures to make sure you keep
your LAN free of viruses. It's particularly important that you follow
the guidelines there on access rights and supervisor privileges. If
you periodically boot each workstation from a write- protected floppy
and do a full check of that PC, you can be assured of maximum
protection for your LAN.
Integrity Master (tm) - 35 - Version 2.22
Chapter Four - Customizing
____________________________________________________________________
Customizing Integrity Master
When you first install Integrity Master, SetupIM does an initial
customization for you based upon your needs and preferences.
Integrity Master offers you a myriad of different options so that you
can set it up to work just the way you want.
From the Integrity Master Options menu, you can control almost all
options that regulate how IM functions. Your option changes may be
either temporary or permanent. To make your changes permanent,
select "Write option changes to disk" from the Options menu. This
will save your option changes on the parameter file. These options
will be in effect the next time you execute IM.
In addition to initially installing IM, SetupIM allows you to change
the less frequently used options. The more advanced options (which
you may never need to change) are segregated onto their own menu.
These options include turning off virus checking, changing which
files IM considers to be programs and deciding where IM will store
your integrity data. SetupIM also allows you to permanently change
the colors that IM uses on the display.
These options are stored on the parameter file (IM.PRM). You may,
if you wish, keep multiple versions of this file around to represent
different sets of options. You can specify a different name for this
file on IM's command line.
The Parameter (Options) File
The parameter file (IM.PRM) contains all the options that control
how IM works. IM and SetupIM look for this file by searching the
following locations:
o the current directory,
o the directory where IM.EXE is located,
o or the root directory on any disk.
Whenever you change any options and save the changes, the
parameter file is rewritten. The option "Write option changes to
disk" on IM's Options menu does this as well as SetupIM.
Integrity Master (tm) - 36 - Version 2.22
T H E O P T I O N S M E N U
You can reach the Options menu from any primary IM menu by hit-
ting the "O" or alt/O keys. From the Options menu, you can control
almost all options that determine how IM works. These options
include all normal day-to-day choices.
.----------.-------.---------------------------------------------.
| Help |Options| Check Initialize ReLoad CoMmands |
.- .-------. .--------------------------. -----------------.
| Write option changes to disk |
| Integrity: CHECKING ON.off=quick update |
| Integrity Update: Ask for prog change |
| Files to Check: Executable programs |
| Files to iNitialize: Executable programs |
| Halt on: ALL changes, adds or deletes |
| Sound -------------------------> ON.off |
| Report: (file or print)--------> on.OFF |
| Video (screen) report ---------> ON.off |
| Ignore Time.date changes ------> on.OFF |
| Only changes reported ---------> on.OFF |
| Exclude: OFF and exclude report OFF |
.------------------------------------------.
In addition to allowing you to set all the above options, the Options
menu displays the current settings of these options. The options that
have "on/off" settings, are toggled between their "on" and "off" states
by hitting the ENTER key. The current setting of the option is
displayed in capital letters, as well as in a distinctive color.
Write option changes to disk
This allows you to write any option changes to the parameter file,
making your option changes effective the next time you execute IM
also. This option does not exist on the SetupIM version of the
Options menu.
Integrity: CHECKING ON/off=quick update
This is the most crucial item on the Options menu. Hitting the
ENTER key toggles IM between doing full integrity checking and
doing only quick integrity data updating. When you hit ENTER,
either "Checking ON" or "OFF=Quick update" will be in all
capital letters and in a different color (on most displays). This
discloses whether full integrity checking is on or off. The status of
integrity checking is also always visible on the fourth line at the top
of the screen.
Quick update mode provides a very fast way to bring all your
integrity data up to date. IM reads and integrity checks only files
whose size, time stamp or date stamp have changed. To detect file
corruption and viruses, it's essential to regularly turn "Checking
ON" to do full integrity checks.
Integrity Master (tm) - 37 - Version 2.22
Integrity Update:
IM normally updates the integrity data describing a file whenever the
file changes (unless the file is affected by a known virus or a disk
error). This option allows you control when IM updates the integrity
data describing changed files. This option is handy if you expect to
find some damaged files and you want to save the old integrity data
so that you can restore the file and then use IM to verify that
file is back to its original state. The Option menu item itself
displays the current setting for this option. Integrity Update
can have five values:
"On for any changes" - this is the normal mode where the integrity data
will be updated whenever a file changes
"Off for any changes" - IM will NOT overwrite the old integrity data
with the new when a file changes.
"Off for prog changes"- IM will NOT overwrite the old integrity data
with the new when an executable file
(a program) changes.
"Ask for any changes" - IM will ask you if it should overwrite the old
integrity data with the new when a file
changes.
"Ask for prog changes"- IM will ask you if it should overwrite the old
integrity data with the new when an executable
file (a program) changes.
The right most part of the second line at the top of your screen will
also display an indication if you have Integrity Updating set to
anything other than "On".
Files to Check:
You can use this option to limit IM's checking to only executable
or source programs. Even if you are interested only in virus
detection, I strongly recommend that you also periodically set this
option to check all files, so that you can be alerted to the other
(more common) causes of file damage. The Advanced menu in
SetupIM allows you to change which files IM considers to be
executable or source programs.
Files to iNitialize:
Use this option to limit IM's initializing of integrity data to only
executable or source programs. Even if your primary interest is
viruses only, I strongly recommend that you set this option to read
all files, so that you can be alerted to the other (more common)
causes of file damage. The Advanced menu in SetupIM allows you
to change which files IM considers to be executable or source
programs.
Integrity Master (tm) - 37b - Version 2.22
Halt on: ALL changes
When IM is checking your files for changes, it lists each new
change that it detects at the top of the report screen. The other
changes on the screen shift downward (scroll) as each new line is
added at the top of the screen. By setting the halt options, you
control when this scrolling will pause and wait for you to hit a key.
This prevents a change from scrolling off the screen without you
having seen it. The halt options appear on this menu:
.---------------------------------.
| Halt on: |
| All detected differences |
| Changed files only |
| Changes to Executable programs |
| Changes to any Program |
| File corruption or worse |
| Serious problems |
| Emergencies Only (not viruses) |
.---------------------------------.
If you halt scrolling on "All detected differences", anytime a line
written to the report screen is about to disappear off the bottom of
the screen, the display will pause and wait for you to hit a key to
acknowledge that you've seen all the lines on the display. After
you hit a key, the display will not pause until all the lines currently
on the screen have scrolled off and a new unseen line is about to
scroll off the screen.
If you halt scrolling on "Changed files only", the scrolling will
pause only when a modified file is about to disappear off the
bottom of the screen. After you hit ENTER, the display will not
stop scrolling until a changed file is about to scroll off the bottom.
This changed file must not have been on the screen during the prior
pause.
If you halt scrolling on "Changes to Executable programs", the
scrolling will pause only when a program is about to disappear off
the bottom of the screen. After you hit ENTER, the display will
not stop scrolling until a program that was not on the previous
display is about to scroll off the bottom. You can use the
"Advanced option" menu in SetupIM to check or change what IM
considers to be executable programs.
If you halt scrolling on "Changes to any Program", the scrolling
will pause only when a program (either source or executable) is
about to disappear off the bottom of the screen. After you hit
ENTER, the display will not stop scrolling until a program that
was not on the previous display is about to scroll off the bottom.
You can use the "Advanced option" menu in SetupIM to check or
change what IM considers to be either source or executable
programs.
If you halt scrolling on "File corruption or worse", only signs of
viruses, corrupted files, or possible hardware errors will pause the
display.
Integrity Master (tm) - 38 - Version 2.22
If you tell IM to halt on "Serious problems", then the display will
pause only when it detects a virus or critical error such as a
hardware error. This affects scrolling in the same way as using the
"/N" parameter on the command line. If you set halt to this option,
be sure that IM is writing a report to a file or to the printer,
otherwise you may miss some important warnings.
If you tell IM to halt on "Emergencies Only", then the display will
almost never pause. IM will continue processing even if it detects
a known virus in a file or can't read the disk. IM will only stop if
it considers it dangerous to continue or if you're in danger of losing
important information. This affects scrolling in the same way as
using the "/NE" parameter on the command line. If you set halt to
this option, be sure that IM is writing a report to a file or to the
printer, otherwise you may miss some important warnings.
You can always halt scrolling by hitting the "P" key.
Sound -------------------------> ON/off
IM will provide beeps and tones to alert you that something
important has happened (or that you've hit an unsupported key).
Hitting ENTER toggles whether you will hear these sounds.
Integrity Master (tm) - 39 - Version 2.22
Report: (xxxxxxxxxxxxx)--------> on/OFF
This allows you to turn the report file off or to ask IM to write a
report of its activities to either the printer or a disk file. The
"xxxxxxxxx" on the option line represents the name of the current
report file or printer. The disk file can be automatically named by
IM or can be any file of your choice. Please see "The Report
File" in Chapter three for more details on these options. This
option line, along with the third line from top of IM's screen,
display the status of the report file.
Video (screen) report ---------> ON/off
If you have a very slow video board (such as some very old CGA
adapters), IM will run a little faster if you turn the screen report
off. (Be sure to turn the report file on!)
Ignore Time/date changes ------> on/OFF
Sometimes the DOS time or date stamp on a file will change, but
the file itself won't change. If you do not want to have such files
reported as changed, set this option to "ON".
Only changes reported ---------> on/OFF
If you do not want reports of added or deleted files, turn this option
"on". If "Only changes reported" is set to "on", then you will see
only reports of file changes; IM will not report added or deleted
files. IM will still update the integrity data to reflect the added or
deleted files, but it won't report these files. All other processing
also continues normally including the detection of companion
viruses (viruses that appear only as added files).
Exclude: ON and exclude report OFF
Selecting this option will pop up the Exclude menu:
.-----------------------------------------.
| IM will optionally exclude selected |
| files or directories from checking. |
| |
| Please hit ESCape when you are done. |
|-----------------------------------------|
| Exclude checking is now OFF; turn it ON |
| Reporting is now OFF; turn it ON |
| Select files or directories to exclude |
.-----------------------------------------.
The Exclude menu allows you to exclude files or entire directories
from checking, scanning, or initializing. The bottom line of the
Options menu along with the lines on the Exclude menu show
whether excluding of files or directories is turned on and whether
reporting of excluded objects is turned on. Either may be toggled
on or off at the press of a key. If reporting of excluded files is
"ON" and excluding itself is "ON", then a line will appear on the
report every time a file or directory is bypassed from checking,
scanning, or initializing. The line will list the particular file or
directory that was excluded.
Integrity Master (tm) - 40 - Version 2.22
You may exclude a file by specifying the precise file name or using
the wild card characters to specify a series of files. You can also
exclude all files within a directory by excluding that directory from
checking. Either files or directories can be excluded based on wild
cards. For example, you can tell IM to ignore any directory
beginning with the characters "IM" by using the wild card: "IM*".
Or you could tell IM to ignore all your ZIP files (all filenames
ending in ".ZIP") by using the wild card "*.ZIP".
When you're entering file or directory names to exclude, you may
use the DOS wild card characters: * and ?. The "*" character
matches zero or any number of characters, while "?" matches one
and only one character. Some examples:
This name: Would exclude: But not:
A?.* AB.ABC, AC.D ABC.ABC, A.DEF, AX
??.ABC XY.ABC, AB.ABC A.ABC, XYZ.ABC
A*.A? A.AB, ABC.AX A.CB, A.ABC
Note that a wild card in the form "X*" will exclude any filename
beginning with "X" (with or without an extension) while "X.*" will
exclude only files which have an extension.
If a file or directory is excluded, Integrity Master will no longer
record information for it. If integrity data already exists, then IM
will remove it. To make sure you are aware of this, IM will
always notify you that it is updating the integrity data. For this
reason, you may see changes reported in a directory when you
otherwise wouldn't expect any. By asking IM to report what is
being excluded you can see exactly what is being affected.
Be very careful when excluding directories. If a directory is
excluded, IM will not look at any of the files in that directory or
any of the subdirectories within that directory. This means you can
exclude an entire series of subdirectories (and their associated files)
by excluding a single directory.
If you un-exclude files and directories, they will appear as "added"
the next time you run a check.
Integrity Master (tm) - 41 - Version 2.22
OPTIONS IN SETUPIM
When you execute SetupIM for the first time, the Integrity Advisor(tm)
will set your options in a way most likely to meet your needs and
interests. You can later go back and change any of the options that
were set for you. If you specify that it's not your first install of IM,
you will see this menu:
.--------------------------------------.
| Select an option and hit ENTER: |
| |
| Overview of IM setup and operation |
| Change how Integrity Master operates |
| Repeat the install on this PC |
| Install IM on another PC |
| Quit |
.--------------------------------------.
From this menu, you can select "Change how Integrity Master
operates" and hit ENTER. This brings you to the Change menu:
.--------------------------------------.
| Select an option and hit ENTER: |
| |
| Screen display mode |
| Integrity data options |
| Advanced options |
| Update hardware configuration |
| Exit - save any changes and end |
| Abort - Quit and abandon any changes |
.--------------------------------------.
OPTIONS AVAILABLE ONLY IN SETUPIM
SetupIM allows you to change certain options that you would only
want to change very rarely. All the options on this menu are not
available within IM itself.
SCREEN DISPLAY MODE
This allows you to set the screen colors as explained in the Chapter
Two section titled Screen Colors. Unless you have problems reading
the screen, I strongly recommend that you allow IM to continue to
operate in automatic video mode. This way it will choose whatever
colors are best for your video equipment.
Integrity Master (tm) - 42 - Version 2.22
INTEGRITY DATA OPTIONS
This allows you to change how IM stores the integrity data describing
your files and system sectors. You can change the name, attribute, or
the location of your integrity data files. You can also use this menu
selection to check what the characteristics of your integrity data files
are.
INTEGRITY DATA FILE ATTRIBUTES
You can ask IM to make your integrity data files hidden, read- only,
or both. Unless you are used to working with read-only and hidden
files and consider yourself fairly expert with DOS, I suggest that you
not set these attributes. There are quite a few programs that will
cause confusing results when they work with hidden or read-only files.
These attributes can easily by overridden by a knowledgeable user or
program.
INTEGRITY DATA FILE NAMES:
You can choose the names that IM will use for the integrity data
files. These filenames can be either fixed or variable. If you
originally installed a IM version 1.24b or earlier, your integrity
data was stored in files named ")(.ID". Each file had this same fixed
name. You can now choose your own name for these files or ask IM to
use variable names.
VARIABLE INTEGRITY DATA FILE NAMES
To make it more difficult for rogue programs to attack your
integrity data files, IM can use variable file names. Both the file
name and the extension contain some characters which will be
different for each file. Plus, the remainder of the file name will
be different for each installation. When you first install, the
Integrity Advisor usually selects variable file names to store your
integrity data. SetupIM will then explain how these file names are
formed for your particular installation. It will also record this
in the IMPROC.TXT file in case you need to quickly check this later.
If you install on another PC, these file names will be different
unless you use the original parameter file. To make these files
easier for you to find, you may choose part of both the file name
and the extension.
FIXED INTEGRITY DATA FILE NAMES
If you choose fixed file names then every integrity data file will
have the same name. This makes it very easy to locate these files.
The drawback is that this also makes it very easy for someone else
to locate your integrity data files if you keep them in the same
directory with the files they describe. A destructive program could
deliberately delete these files, causing loss of protection.
Integrity Master (tm) - 43 - Version 2.22
LOCATION OF INTEGRITY DATA
As IM checks your files, it must store the integrity data that
describes these files. Using SetupIM you can change where IM
stores these files. There are two options:
1) It can store the integrity data in the same directory along with
the files being checked, or
2) It can store the integrity data on a separate disk (usually a
floppy).
Storing the integrity data on a floppy gives you additional
protection against a virus or a person changing a file and then
modifying the integrity data to cover up the change. For viruses,
this threat is fairly remote since the virus would have to be written
specifically to attack files created by IM. This would be very
difficult since these files are encrypted differently on each PC.
Storing the integrity data with the files being checked is usually
easier and more flexible since the integrity data can be copied
along with the files. This also makes it easy for you to use IM to
verify that you've made a good copy when you copy or move the
files. If you want to restore an old copy of a file from a backup,
you can restore the integrity data along with the file and then ask
IM to check that the file was restored correctly. If you move your
files, it's easier to move the integrity data along with the files if it's
stored in the same directory as the files.
Update hardware configuration
Please use this option whenever you change the configuration of disk
drives on your computer, or if you use software that changes the
assignment of DOS logical disk letters (A to Z) to your physical disk
drives. SetupIM will check the capabilities of each of your installed
disk drives. This will produce a display showing the drives that
SetupIM recognizes. It will also list any drives that do not contain
DOS boot sectors and any that do not have partition sectors (master
boot records).
Exit - save any changes and end
This updates the parameter file (IM.PRM) with any option changes
you've selected, and exits SetupIM.
Abort - Quit and abandon any changes
This Allows you to exit SetupIM without writing any of your
changes. All option changes will be as they were before you entered
SetupIM.
Integrity Master (tm) - 44 - Version 2.22
THE ADVANCED OPTION MENU
If you select this option on the SetupIM change menu, the Advanced
option menu will appear.
.------------------------------------------------.
| Select an option and hit ENTER: |
| (Hit ESCape when you're done) |
| |
| Specify Names of hidden system files |
| Define which files are Executable programs |
| Define which files are Source programs |
| Check for virus in memory is ON; turn it off |
| General virus checking is ON; turn it off |
.------------------------------------------------.
This menu is intended for more technically advanced users. Most IM
users should never need to use this menu. When you're finished
making changes on this menu, just hit ESCape to go back to the
previous menu. The Advanced Option menu offers you these options:
Specify Names of hidden system files
Selecting this option will allow you to change the names of the files
that IM recognizes as the hidden system files. This option is only
needed on nonstandard PCs that don't use the standard Microsoft
or the IBM names for the hidden system files. The files SetupIM
recognizes by default are: IBMBIO.COM, IBMDOS.COM,
IO.SYS and MSDOS.SYS. If you execute "IMCHECK *.*", in
your root directory and you don't see two of the above files, but
instead see two other similarly named files, you may wish to use
this option so IM recognizes those files. If you don't understand
what this is all about, don't worry. IM's ability to recognize your
hidden system files is NOT that important. It simply allows IM to
provide more specific information in two warning messages.
Integrity Master (tm) - 45 - Version 2.22
Define which files are Executable programs
This option allows you to specify which file extensions (the letters
after the "." in the file name) IM should consider to represent
executable programs. This is important for three reasons:
1) Non-executable files are not normally checked for known
viruses.
2) IM provides special warning when executable programs change.
3) If you use the Options menu to limit checking to executable
programs, only these files will be checked.
Initially, IM will consider files ending in the following extensions
to be executable programs:
Numeric extensions such as .123
.OV? (where ? can be any character) .DRV
.BAT .EXE
.BIN .PIF
.COM .SYS
.DLL .SWP
Note that not all these files can actually be affected by viruses, but
all these files in one way or another contain instructions that are
executed by your PC.
Define which files are Source programs
This option allows you to specify which file extensions (the letters
after the "." in the file name) IM should consider to be source
programs. Source programs are the programs a programmer
would use to create executable programs. If you are not a
programmer then you probably don't care about this option. This
option is intended mostly to provide programmers with extra
warning if something has changed their source code.
Integrity Master (tm) - 46 - Version 2.22
Check for virus in Memory
Selecting this option will toggle the checking of memory for known
viruses on or off. If you toggle memory checking on, the option
line will be changed to read:
Check for virus in memory is ON; turn it off.
This indicates that memory checking is now "ON". If you hit
ENTER at this point, you will turn it "off", and the option will
then read:
Check for virus in memory is OFF; turn it on.
Having this option "ON" allows IM to detect known viruses that
are resident in memory. If you always cold boot from a known
good copy of DOS on a write-protected diskette, you could safely
turn this option off, since there would be no way for a virus to be
resident in memory. Since it's hard to guarantee that you always
cold boot, please leave resident memory checking turned on. If you
execute IM multiple times and you don't want to wait for the
memory check to complete, you can use the"/B" (Bypass) com-
mand line parameter to bypass the resident memory check.
General virus checking
Selecting this option and hitting enter will toggle checking of files
for known viruses on or off. If you have absolutely no interest in
viruses, you can speed up IM's initialize processing and its check
processing (only when it encounters changed files) by 10 to 20
percent. Since this option imposes so little overhead in normal file
checking, I suggest everyone leave it turned on.
Integrity Master (tm) - 47 - Version 2.22
Chapter Five - Errors
____________________________________________________________________
Error recovery:
IM replaces the normal DOS error recovery routines with its own
more sophisticated routines. If you encounter hardware errors, you'll
generally see a message announcing what happened followed by a
screen that will give you the option of retrying the failed operation,
aborting (allowing whatever IM was trying to do, to fail), or other
options depending upon the circumstances. These other options may
include "Shelling to DOS". Shelling allows you to temporarily exit
IM and execute any DOS command (such as formatting a disk) you
wish. You then return to IM by typing the EXIT command. This
returns you to the same point in IM, just as if you had never left.
Solving problems:
If you encounter a problem with IM, please read file
QUESTION.TXT (for a list of common questions and answers) and
file SUPPORT.DOC (for the complete procedure on how to quickly
get technical support). File DISKHELP.TXT contains specific
information on how to handle problems if IM won't recognize your
disk drive. You can use IMPRINT or IMVIEW to read any of these
files. Example: "IMVIEW SUPPORT.DOC"
Answers to Common Questions:
File QUESTION.TXT contains common questions and answers
regarding IM. You can read these by entering the command
"IMVIEW QUESTION.TXT" at the DOS prompt or print with the
command "IMPRINT QUESTION.TXT". Here are some examples
of common questions:
Q: Sometimes IM comes up with different colors on the screen than
before. What's going on?
A: IM checks the DOS video mode indictor on your PC to see if you
are in color or monochrome mode, as well as directly checking
your video adapter. This allows you to use the DOS "MODE
BW80" to indicate that a two-color display is present on a color
adapter card. Some programs change this value to an incorrect
value. If this happens to you, use the DOS mode command to set
the video mode back to the correct state. For example, enter
"MODE CO80" to restore normal color mode. You can also use
the command line override (or SetupIM) so IM comes up using
whatever colors you prefer. "IM /C" would force IM to run in
color mode.
Integrity Master (tm) - 48 - Version 2.22
Q: IM detected a virus on my PC. I reloaded my system sectors and
either deleted or reloaded all infected files, yet the virus keeps
coming back! What should I do?
A: Somewhere a virus is eluding your checks. Please check the
following:
o Did you install IM after cold booting from a clean floppy? It's
absolutely vital to do a cold boot before checking.
o Are you using a task switcher (or multi-tasker) such as
windows? If so, then this program may be saving some of your
infected programs in its "swap" file. This file often ends in the
letters ".SWP". Delete this file if it exists.
o Be sure you check ALL files and floppies that come into contact
with your computer. You may have missed a file or diskette
somewhere. Please take the extra time and check them all.
o It's possible that viral code is hidden somewhere other than an
executable file. IM normally checks only executable files
(programs and overlays) for known viruses. Try selecting "Disk
for known Viruses" on the Check menu and selecting "Check
All files" on that menu. This will check all files as well as
system sectors on your disk. Also, check any other disks that
you've been using.
Q: I was just checking a diskette for viruses and IM detected the
DataCrime 2 virus in a file. When I restarted IM, it detected the
DataCrime virus resident in memory! I never executed the
program that was infected, so how did the virus get control of my
PC?
A: The virus wasn't really resident or in control of your PC. What
happened was that a piece of the viral code was left somewhere in
memory - probably in one of DOS's file buffers. Although IM
takes great pains to clear its own buffers and areas of memory, it's
not unusual to get a false indication of the virus being active in
memory after detecting a virus in a file or system sector.
Q: I just did a "DIR" on a diskette which had the "Stoned" boot
sector virus. When I ran IM, it reported the virus was active in
memory. Can I get a virus by just doing a DIR?
A: No; you cannot get infected unless you execute an infected
program or boot from an infected diskette. When you did the
"DIR", a copy of the infected boot sector was read into memory.
IM detected this copy in memory. Although the virus is in
memory, this is harmless since the virus code is never executed.
Integrity Master (tm) - 49 - Data Integrity and Viruses
PART TWO
Data Integrity and Viruses
___________________________________________
How do I make sure that my programs and files
really are safe?
What threats are even more likely to damage my
data than viruses?
What really works against viruses?
What doesn't work against viruses?
Why are viruses so dangerous?
How do I kill a virus?
___________________________________________
Copyright 1990-1994, Wolfgang Stiller, All rights reserved.
Integrity Master (tm) - 50 - Data Integrity and Viruses
Integrity Master (tm) - 51 - Data Integrity and Viruses
PART TWO - DATA INTEGRITY AND VIRUSES
CHAPTER ONE - THREATS TO YOUR DATA
____________________________________________________________________
INTRODUCTION - VIRUSES GET ALL THE GLORY
Do you have data or programs on your PC which you can't afford to have
unexpectedly damaged? How can you make sure that your data is safe? To
protect the integrity of your data, you must first understand the nature
of the threats against it.
The most publicized threats to your computer are software-based attacks
often lumped together as "viruses" by the media. Although viruses are
often over sensationalized by media coverage, they do present a very
real menace to your data. (See the section in this chapter titled How
serious are viruses?.) Even if a virus never attacks your PC, it is
almost inevitable that system glitches will someday corrupt data or
programs on your PC. Considering that viruses are but one threat to
your data and not the most likely threat by far, it's ironic that so
many people have anti-virus software but so few people take steps to
protect the integrity of their programs and data from other hazards.
Can anyone afford NOT to know that each and every byte on their disk is
undamaged?
So what's the explanation? Why do so few people take steps to assure
the integrity of the data on their PC? The main reason is that data
integrity gets almost no media coverage, (even in the trade journals),
while a virus story may make the local evening news. The result is that
people just don't give data integrity a second thought. It's all too
easy to take the reliability of our modern PCs for granted -- and, as
you'll see, all too dangerous!
You may be reading this primarily because you're interested in viruses.
If that's true, then, for you, the media attention to viruses will have
had a very beneficial effect. You are about to learn how to protect
your PC against much more than just viruses! Data integrity is not a
very glamorous subject, yet it's both crucial and fundamental to using
any computer. Without positive assurance of data integrity, computers
cannot be depended upon to process any type of important data. How
would you respond if someone were going to change a byte of data
somewhere at random on your disk? You'd be pretty upset -- right?
Well, the odds are, it has already happened but you were not aware of
it. Perhaps the result was that a program quit working or CHKDSK found
lost or cross-linked clusters. Or per- haps, if you're lucky, the
damage was to some inconsequential part of your disk.
Integrity Master (tm) - 52 - Data Integrity and Viruses
Let's explore the different threats to your files and programs:
HARDWARE AND POWER FAULTS
These are well known but also all too common. We all know that when
your PC or disk get old, they might start acting erratically and damage
some data before they totally die. Unfortunately, hardware errors
frequently damage data on even young PCs and disks.
Your PC is busy writing data to the disk and the lights go out!
"Arghhhh!" Is everything OK? Maybe so, but it's vital to know for sure
if anything was damaged. If your disk drive is starting to fail, you
can have the same problem. Regrettably, it's not a question of "if",
but a question of "when" in regard to disk failure. There are tools
(NORTON, MACE, PCtools, etc) to assist in recovery from disk problems,
but how do you know all the data is OK? These tools do not always
recover good copies of the original files. It's vital to have some way
to check that these tools really do their job correctly.
You can have hardware problems on a perfectly healthy PC if you have
devices installed that do not properly share interrupts. This problem
is getting more and more frequent as we see multiple adapters installed
in a PC that use the same interrupt (IRQ). Sometimes problems are
immediately obvious, other times they are subtle and depend upon certain
events to happen at just the wrong time, then suddenly strange things
happen!
FINGER CHECKS (TYPOS AND "OOPS! I DIDN'T MEAN TO DO THAT.")
These are an all too frequent cause of data corruption. This commonly
happens when you are intending to delete or replace one file but
actually get another. By using wild cards, you may experience a really
"wild" time. "Hmmm I thought I deleted all the *.BAK files . . . but
they're still here . . . something was deleted . . . what was it? . . .
or was I in the other directory?" Of course if you're a programmer or
if you use sophisticated tools like Norton's sector editor (NU), then
your fingers can really get you into trouble!
MALICIOUS OR CARELESS DAMAGE
Someone may accidentally or deliberately delete or change a file on your
PC when you're not around. If you don't keep your PC locked in a safe,
then this is a risk. Who knows what was changed or deleted? Wouldn't
it be nice to know if anything changed over the weekend? Most of such
damage is done unintentionally by someone whom you probably know. This
person didn't mean to cause trouble; they simply didn't know what they
were doing when they used your PC.
Integrity Master (tm) - 53 - Data Integrity and Viruses
SOFTWARE PROBLEMS
This category accounts for more damage to programs and data than any
other. We're talking about non-malicious software problems here, not
viruses. Software conflicts, by themselves, are much more likely
threats to your PC than virus attacks.
We run our PCs today in a complex environment. There are many resident
programs (TSRs such as Sidekick) running simultaneously with various
versions of DOS, BIOS and device drivers. All these programs execute at
the same time, share data and are vulnerable to unforeseen interactions
between each other. Naturally, this means that there may be some
subtle bugs waiting to "byte" us. Anytime a program goes haywire,
there's the risk it may damage information on disk.
There's the further problem that not all programs do what we hope they
will. If you have just undeleted a file, did you really get all the
correct clusters back in the right order? When CHKDSK "fixes"
your disk for you, isn't it essential to know exactly what files it
changed to do its job? This is one more reason why everyone must have
the capability to verify data integrity.
SOFTWARE ATTACKS
These are programs written deliberately to vandalize someone's computer
or to use that computer in an unauthorized way. Even though some
viruses do not intentionally damage your data, I consider all viruses to
be malicious software since they modify your programs without your
permission, with occasional disastrous results. There are many forms of
malicious software; sometimes the media refers to all malicious software
as viruses. It's important to understand the distinction between the
various types. Let's examine the different types of malicious software:
LOGIC BOMBS
Just like a real bomb, a logic bomb will lie dormant until triggered by
some event. The trigger can be a specific date, the number of times
executed, a random number, or even a specific event such as deletion of
an employee's payroll record. When the logic bomb is triggered, it
will usually do something unpleasant. This can range from changing a
random byte of data somewhere on your disk to making the entire disk
unreadable. Changing random data may be the most insidious attack
since it generally causes substantial damage before anyone notices that
something is wrong. It's vital to have some data integrity software in
place so that such damage can be quickly detected. Although you can
detect it after the fact, there is unfortunately no way to prevent a
well written logic bomb from damaging your system. On the other hand, a
logic bomb that uses standard DOS or BIOS requests to do its dirty work
can be caught by most interceptor type programs (see Chapter Two).
Integrity Master (tm) - 54 - Data Integrity and Viruses
TROJANS
These are named after the Trojan horse, which delivered soldiers into
the city of Troy. Likewise, a trojan program is a delivery vehicle for
some destructive code (such as a logic bomb or a virus) onto a computer.
The trojan program appears to be a useful program of some type, but when
a certain event occurs, it does something nasty and often destructive to
the system.
WORMS
A worm is a self-reproducing program that does not infect other programs
as a virus will, but instead creates copies of itself, that create even
more copies. These are usually seen on networks and on
multi-processing operating systems, where the worm will create copies of
itself that are also executed. Each new copy will create more copies
quickly clogging the system. The so-called ARPANET/INTERNET "virus"
was actually a worm. It created copies of itself through the ARPA
network, eventually bringing the network to its knees. It did not
infect other programs as a virus would, but simply kept creating copies
of itself that would then execute and try to spread to other machines.
VIRUSES
Viruses are a cause of much confusion and a target of considerable
misinformation even from some so-called virus experts. Let's define
what we mean by virus:
A virus is a program that reproduces its own code by attaching itself
to other programs in such a way that the virus code is executed when the
infected program is executed.
You could probably also say that the virus must do this without the
permission or knowledge of the user, but that's not a vital distinction
for purposes of our discussion here.
Most viruses do their "job" by placing self-replicating code in other
programs, so that when those other programs are executed, even more
programs are "infected" with the self-replicating code. This
self-replicating code, when triggered by some event, may do a
potentially harmful act to your computer. Viruses are initially
distributed in the form of a trojan. In other words, the virus code has
been planted in some useful program. Since the virus infects other
useful programs, absolutely any piece of executable code will suddenly
become a trojan delivery vehicle for the virus.
Another way of looking at viruses is to consider them to be programs
written to create copies of themselves. These programs attach these
copies onto other programs (infecting these programs). When one of
these other programs is executed, the virus code (which was attached to
that program) executes, and links copies of itself to even more
programs.
GENERAL VIRUS BEHAVIOR
Viruses come in a great many different forms, but they all potentially
have two phases to their execution, the infection phase and the attack
phase:
1) When the virus executes it will infect other programs. What's
often not clearly understood is precisely WHEN it will infect the
other programs. Some viruses infect other programs each time
they are executed; other viruses infect only upon a certain trigger.
This trigger could be anything; it could be a day or time, an
external event on your PC, a counter within the virus, etc.
Modern viruses have become more selective about when they
infect programs. Being selective improves the virus' chance to
spread; if they infect too often, they will tend to be detected before
they have enough time to spread widely. Virus writers want their
programs to spread as far as possible before anyone notices them.
This brings up an important point which bears repeating:
IT IS A SERIOUS MISTAKE TO EXECUTE A PROGRAM A
FEW TIMES - FIND NOTHING INFECTED AND PRESUME
THERE ARE NO VIRUSES IN THE PROGRAM. YOU CAN
NEVER BE SURE THAT THE VIRUS SIMPLY HASN'T
TRIGGERED ITS INFECTION PHASE!
Integrity Master (tm) - 56 - Data Integrity and Viruses
Many viruses go resident in the memory of your PC in the same way as
terminate and stay resident (TSR) programs such as Sidekick. This
means the virus can wait for some external event before it infects
additional programs. The virus may silently lurk in memory waiting
for you to insert a diskette, copy a file, or execute a program,
before it infects any other programs. This makes these viruses more
difficult to analyze since it's hard to guess what trigger condition
they use for their infection. Resident viruses frequently corrupt the
system software on the PC to hide their existence. This technique is
called "stealth" and I'll cover this in more detail shortly.
2) The second phase is the attack phase. Many viruses do unpleasant
things such as deleting files or changing random data on your disk,
simulating typos or merely slowing your PC down; some viruses
do less harmful things such as playing music or creating messages
or animation on your screen. Just as the virus's infection phase
can be triggered by some event, the attack phase also has its own
trigger. Viruses usually delay revealing their presence by
launching their attack only after they have had ample opportunity
to spread. This means that the attack may be delayed for years
after the initial infection. The attack phase is optional, many
viruses simply reproduce and have no trigger for an attack phase.
Does this mean that these are "good" viruses? No, unfortunately
not! Anything that writes itself to your disk without your
permission is stealing storage and CPU cycles. This is made
worse since viruses that "just infect", with no attack phase,
damage the programs or disks they infect. This is not an
intentional act of the virus, but simply a result of the fact that
many viruses contain extremely poor quality code. One of the
most common viruses, the STONED virus is not intentionally
harmful. Unfortunately, the author did not anticipate the use of
anything other than 360K floppy disks. The virus will try to hide
its own code in an area on 1.2mb diskettes, resulting in corruption
of the entire diskette.
Integrity Master (tm) - 57 - Data Integrity and Viruses
Now that we've examined general virus behavior, let's take a closer
look at the two major categories of viruses and how they operate.
SYSTEM SECTOR VIRUSES
These are viruses that plant themselves in your system sectors.
System sectors are special areas on your disk containing programs
that are executed when you boot your PC. Sectors are not files but
simply small areas on your disk that your hardware reads in single
chunks. Under DOS, sectors are most commonly 512 bytes in length.
These sectors are invisible to normal programs but are vital for
correct operation of your PC. They are a common target for viruses.
There are two types of system sectors found on DOS PCs:
DOS Boot Sectors
The very first sector on disk or diskette that DOS is aware of is the
boot sector. From a DOS perspective, this is the first sector on
the disk. This sector can contain an executable program whether
the disk is bootable or not. Since this program is executed every
time you power on or boot your PC, it is very vulnerable to virus
attack. Damage to this sector can make your disk appear to be
unreadable. This sector is rewritten whenever you do a "SYS" or
a "FORMAT /S" to a disk.
Warning: Even a non-bootable floppy can contain a virus in the
boot sector. If you leave the floppy in your PC when you power
on or boot, you will be infected even though the PC won't
successfully boot from that floppy.
Partition Sectors
On hard (fixed) disk drives, the very first sector is the partition
sector (also known as the master boot record or partition table).
Each physical hard disk drive has one of these sectors. A single
physical disk can be partitioned into one or more logical disks. For
example, you may have a physical drive partitioned into C: and D:
logical disks so that your single physical disk appears (to DOS) to
be two logical disks. The single partition sector contains the
information that describes both logical disks. If the partition sector
is damaged, then DOS may not even recognize that your disk
exists.
The partition sector also contains a program that is executed every
time you power up or boot your PC. This program executes and
reads the DOS boot sector that also contains a program. Many
viruses plant their code in the partition sector.
Integrity Master (tm) - 58 - Data Integrity and Viruses
System sector viruses modify the program in either the DOS boot
sector or the partition sector. Since there isn't much room in the
system sector (only 512 bytes), these viruses usually have to hide
their code somewhere else on the disk. These viruses sometimes
cause problems when this spot already contains data that is then
overwritten. Some viruses, such as the Pakistani BRAIN virus, mark
the spot where they hide their code as bad clusters. This is one
reason to be alarmed if CHKDSK suddenly reports additional bad
sectors on your disk. These viruses usually go resident in memory on
your PC, and infect any floppy disk that you access. Simply doing a
DIR on a floppy disk may cause it to be infected. Some viruses will
infect your diskette immediately when you close the drive door.
Since they are active in memory (resident), they can hide their
presence. If BRAIN is active on your PC, and you use a sector editor
such as Norton's NU to look at the boot sector of an infected diskette,
the virus will intercept the attempt to read the infected boot sector and
return instead a saved image of the original boot sector. You will see
the normal boot sector instead of the infected version. Viruses that
do this are known as stealth viruses.
In addition to infecting diskettes, some system sector viruses spread
by also infecting files. Viruses of this type are called "multipartite"
(multiple part) viruses. Since they can infect both files and sectors
have more avenues to spread and are more difficult to remove.
File Viruses
In terms of sheer number of viruses, these are the most common kind.
The simplest file viruses work by locating a type of file that they know
how to infect (usually a file name ending in ".COM" or ".EXE") and
overwriting part of the program they are infecting. When this program is
executed, the virus code executes and infects more files. These
overwriting viruses do not tend to be very successful since the
overwritten program rarely continues to function correctly and the virus
is almost immediately discovered. The more sophisticated file viruses
save (rather than overwrite) the original instructions when they insert
their code into the program. This allows them to execute the original
program after the virus finishes so that everything appears normal.
Just as system sector viruses can remain resident in memory and use
"stealth" techniques to hide their presence, file viruses can hide this
way also. If you do a directory listing, you will not see any increase
in the length of the file and if you attempt to read the file, the virus
will intercept the request and return your original uninfected program
to you. This can sometimes be used to your advantage. If you have a
"stealth" virus (such as 4096 or Dir-2), you can copy your program files
(*.EXE and *.COM files) to files with other extensions and allow the
virus to automatically disinfect your files! If you "COPY *.COM
*.CON", and then cold boot your PC from a known good copy of DOS and
"REN *.CON *.COM", this will disinfect the renamed files.
Integrity Master (tm) - 59 - Data Integrity and Viruses
Some file viruses (such as 4096) also infect overlay files as well as
the more usual *.COM and *.EXE files. Overlay files have various
extensions, but ".OVR" and ".OVL" are common examples.
MIRACLE INFECTIONS
Would you believe that a virus can infect your files without changing a
single byte in the file? Well, it's true! There are two types of
viruses that can do this. The more common kind is called the companion
or spawning type virus. This virus infects your files by locating a
file name ending in ".EXE". The virus then creates a matching file name
ending in ".COM" that contains the viral code. Here's what happens;
let's say a companion virus is executing (resident) on your PC and
decides it's time to infect a file. It looks around and happens to find
a file called "WP.EXE". It now creates a file called "WP.COM"
containing the virus. The virus usually plants this file in the
current directory although it could place it in any directory on your
DOS path. If you type "WP" and hit enter, DOS will execute "WP.COM"
instead of "WP.EXE". The virus executes, possibly infecting more files
and then loads and executes "WP.EXE". The user probably won't notice
anything wrong. This type of virus is fortunately easy to detect by the
presence of the extra ".COM" files. There are some instances where it is
normal to have both ".COM" and ".EXE" files of the same name (such as
DOS 5's DOSSHELL) but this is relatively rare.
There is a new type of virus known as a "cluster" virus that infects
your files not by changing the file or planting extra files but by
changing the DOS directory information so that directory entries point
to the virus code instead of the actual program. When you type the name
of the program, DOS loads and executes the virus code, the virus then
locates the actual program and executes it. Dir-2 is an example of this
type of virus and is now spreading rapidly around the world. I am
deliberately keeping the description of this type of virus rather vague
to avoid making it easier to write this type of virus.
POLYMORPHIC VIRUSES
To confound virus scanning programs, virus writers created polymorphic
viruses. These viruses are more difficult to detect by scanning because
each copy of the virus looks different that the other copies. One virus
author even created a tool kit for other virus writers to use called the
"Dark Avenger's Mutation Engine" (also known as MTE or DAME). This
allows someone who has a normal virus to use the mutation engine with
their virus code. If they use the mutation engine, each file infected
by their virus will have what appears to be totally different virus code
attached to it. Fortunately, the code isn't totally different and now
anyone foolish enough to use the muta- tion engine with their virus will
be creating a virus that will be immediately detected by most of the
existing scanners. The existing viruses (such as Pogue, Dedicated,
CoffeeShop, CryptLab, and Groove) which use the mutation engine pose
little threat since they are all simple minded and rather buggy.
Integrity Master (tm) - 60 - Data Integrity and Viruses
VIRUS TOOL KITS
Besides the mutation engine, there are now several tool kits available
to help people create viruses. Several of these programs allow someone
who has no knowledge of viruses to create their own "brand new" virus.
One of these tool kits known as the Virus Creation Laboratory (VCL) has
a very slick user interface with pull down menus and on-line help. You
just pick your choices from the various menus and in a flash you've
created your very own virus. While this sounds like a pretty ominous
development for scanning technology, it's not as bad as it sounds. All
the existing tool kits (such as VCS, VCL and MPC) create viruses that
can be detected easily with existing scanner technology. The danger
with these tool kits lies in the fact that it's possible to create such
a tool kit that could create viruses that really are unique.
Fortunately, this hasn't been done yet, but it's only a matter of time
before this tool kit will be created. This will make scanning-based
products useless; the only reliable way to detect these viruses will be
with an integrity check product.
HOW MANY PC VIRUSES ARE THERE?
There are more PC viruses than all other types of viruses combined (by a
large margin). Estimates of exactly how many there are vary widely and
the number is constantly growing. In 1990, estimates ranged from 200 to
500; then in 1991 estimates ranged from 600 to 1,000 different viruses.
In late 1992, estimates were ranging from 1,000 to 2,300 viruses. Now in
mid 1994, we have over 4,500 viruses in our collection but at least one
persons counts this as over 7,500 viruses. This confusion exists partly
because it's difficult to agree on how to count viruses. New viruses
frequently arise from some idiot taking an existing virus that does
something like put a message out on your screen saying: "Your PC is now
stoned" and changing it to say something like "Donald Duck is a lie". Is
this a new virus? Most "experts" say "yes." This is a trivial change
that can be done in less than two minutes resulting in yet another "new"
virus. Another problem comes from viruses that try to conceal themselves
from scanners by mutating. In other words, every time the virus infects
another file, it will try to use a different version of itself. These
viruses are known as "polymorphic" viruses. One example, the WHALE (a
huge clumsy 10,000 byte virus) creates 33 different versions of itself
when it infects files. At least one person counts this as 33 different
viruses on their list. Many of the large number of viruses known to
exist have not been detected in the wild but probably exist only in
someone's virus collection. Several authors of anti-virus products,
including Mark Washburn and Ralph Burger, have written sophisticated
viruses that are now on the loose, but other viruses that they created
apparently exist only in virus collections.
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David M. Chess of IBM's High Integrity Computing Laboratory reports in
the November 1991 Virus Bulletin that "about 30 different viruses and
variants account for nearly all of the actual infections that we see in
day-to-day operation." We now find that about 38 different viruses
account for all the viruses that actually spread in the wild. How can
there be only 38 viruses active when some "experts" report such high
numbers? This is probably because most viruses are poorly written and
cannot spread at all or cannot spread without betraying their presence.
Although the actual number of viruses will probably continue to be hotly
debated, what is clear is that the total number of viruses is increasing
rapidly, although perhaps not quite as rapidly as the numbers might
suggest.
HOW SERIOUS ARE VIRUSES?
It's important to keep viruses in perspective. There are many other
threats to your programs and data that are MUCH more likely to harm you
than viruses. A well known anti-virus researcher once said that you
have more to fear from a cup of coffee (which may spill) than from
viruses. While the growth in number of viruses now puts this statement
into question, it's still clear that there are many more occurrences of
data corruption from other causes than from viruses. So, does this mean
that viruses are nothing to worry about? Emphatically, no! It just
means that it's foolish to spend much money and time on addressing the
threat of viruses if you've done nothing about the other more likely
threats to your files. Because viruses are deliberately written to
invade and possibly damage your PC, they are the most difficult threat
to guard against. It's pretty easy to understand the threat that disk
failure represents and what to do about it (although surprisingly few
people even address this threat). The threat of viruses is much more
difficult to deal with. There are no "cures" for the virus problem.
Why is this so? We'll explore this in the next chapter on Protecting
Your PC.
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N O T E S :
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CHAPTER TWO - PROTECTING YOUR PC
____________________________________________________________________
"FIXING" YOUR DISK
Damage to your files could be caused by hardware, software or who knows
what. When you are having the problem, your main concern is often not
what caused it, but how to fix the damage. This is where the disk
utility programs offered by Gibson, Norton, Mace, and Central Point are
often very handy. They can sometimes take unreadable data and extract
some of it, or if you have logical damage to your disk such as
cross-linked clusters, these programs (and DOS CHKDSK) may be able to
fix things for you. Unfortunately, things are not always fixed
perfectly when these programs say they are. Using a data integrity
product (such as Integrity Master) will allow you to determine if
everything really was put back together again. More importantly, a data
integrity product can be used to more accurately diagnose what is wrong
to begin with, so you don't attempt a repair which actually makes things
worse.
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GOOF PROTECTION
Who has never accidentally deleted or copied onto the wrong files? Very
few of us! If you have a data integrity product (such as Integrity
Master), a utility package (Norton, Mace, PCtools, etc.) and current
backups, you're all set. You could probably do without the utilities,
but it's rather convenient to be able to unerase files after you
inadvertently delete the wrong ones (this is built into DOS 5). Of
course, a backup program or an undelete utility won't help you if you
didn't notice the incorrect delete when it happened and you now don't
know what to restore or undelete. That's why data integrity software is
a vital component to handling this threat.
INTRUSION PROTECTION
This may not be an issue if you keep your PC is kept locked in a vault
when you're not using it, but otherwise you can never be sure that an
intruder hasn't changed something on your PC. Do you think I am
exaggerating? I am not! The intruder may be your spouse or offspring.
They probably have no intention of changing anything but may be confused
on how to use one of the programs on your PC, with the result that they
inadvertently change the wrong file. On the other hand, you may work in
an environment where someone may want to deliberately do you harm or
perhaps just "play a little joke" on you.
There are programs available that modify the partition sector on your PC
so that the hard disk is unavailable unless someone provides a password.
There are add-in boards that provide the same function. Some PCs (e.g.,
PS/2 PCs) come with a power-up password. You can lock the case to your
PC to make it more difficult to open. You may wish to consider any of
these options depending upon how much risk you face, but please realize
that they can all be bypassed in less than ten minutes by a
knowledgeable user. Surveillance cameras are regarded as a fairly good
deterrent to PC tampering.
While you can't totally stop someone from breaking into your PC, you can
detect and correct the damage. By using an integrity program that
allows you to encrypt the integrity data or store the data off-line (on
floppies), you can detect any illegal tampering, even from a technically
advanced adversary.
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VIRUS DEFENSES
There are various methods in use to protect against viruses. What
follows is a quick review of the viral defense mechanisms that are
widely used today.
SCANNERS
Once a virus has been detected, it is possible to write programs that
look for telltale code (signature strings) characteristic of the virus.
The writers of the scanner then extract identifying strings from the
virus. The scanner uses these signature strings to search memory,
files, and system sectors. If the scanner finds a match, it announces
that it has found a virus. This obviously detects only known, pre-
existing, viruses. Many so-called "virus writers" create "new" viruses
by modifying existing viruses. This takes only a few minutes but creates
what appears to be a new virus. It happens all too often that these
viruses are changed simply to fool the scanners.
The major advantage of scanners is that they allow you to check programs
before they are executed. Scanners provide the easiest way to check for
new software for old (known) viruses. Since they have been aggressively
marketed and since they provide what appears to be a simple painless
solution to viruses, scanners are the most widely used anti-virus
technique.
Too many people seem to regard "anti-virus product" and "scanner" as
synonymous terms. The peril here is that if too many people depend
solely upon scanners, newly created viruses will spread totally
unhindered causing considerable damage before the scanners catch up with
the viruses. An example of this was the attack by the Maltese Amoeba
(Irish) virus in the UK. This virus was not detected prior to its
destructive activation on November 1, 1991. Prior to its attack, it
had managed to spread quite widely and none of the existing (mostly
scanner-based) products detected this virus. According to the December
1991 Virus Bulletin:
"Prior to November 2nd, 1991, no commercial or shareware scanner (of
which VB has copies) detected the Maltese Amoeba virus. Tests showed
that not ONE of the major commercial scanners in use (the latest
releases of Scan, Norton Anti-virus, Vi-Spy, VISCAN, Findvirus, Sweep,
Central Point Anti-virus, et al.) detected this virus."
This indicates the hazard of depending upon scanner technology or active
monitor technology for virus protection.
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Another major drawback to scanners is that it's dangerous to depend upon
an old scanner. With the dramatic increase in the number of viruses
appearing, it's risky to depend upon anything other than the most
current scanner. Even that scanner is necessarily a step behind the
latest crop of viruses since there's a lot that has to happen before the
scanner is ready:
o The virus has to be detected somehow to begin with. Since the existing
scanners won't detect the new virus, it will have some time to spread
before someone detects it by other means.
o The newly discovered virus must be sent to the programmers to analyze
and extract a suitable signature string. This string must be tested
for false positives on legitimate programs.
o This string must be incorporated into the next release of the virus
scanner.
o The virus scanner must be distributed to the customer.
o In the case of retail software, the software must be sent to be
packaged, to the distributors, and then on to the retail outlets.
Commercial retail software takes so long to get to the shelves, that it
is almost certainly out of date. Yet, many retail products depend upon
their scanner for most of their effectiveness.
If you depend upon a scanner, be sure to get the latest version directly
from the author. Also, be sure that you boot from a clean
write-protected copy of DOS before running the scanner; there's a good
chance that the scanner can detect a resident virus in memory, but if it
misses the virus in memory, the scanner will wind up spreading the virus
rather than detecting it. Every susceptible program on your disk could
be infected in a matter of minutes this way!
DISINFECTORS
Most vendors that sell scanners also sell a disinfector (sometimes it's
the same program). A disinfector has the same limitations that a
scanner has, in that it must be current to be safe to use and it's
always one step behind the latest crop of viruses. The disinfector,
however, has an even bigger disadvantage: Many viruses simply cannot be
removed without damaging the infected file. There have also been
numerous reports that files are still damaged even when the program
claims to have disinfected the file. A disinfector like a scanner can
be a very handy tool in your anti-virus arsenal, but it must be used
with care. If you use a disinfector, be sure you have the latest
version direct from the author and use an integrity check to verify that
all files and system sectors are correctly restored.
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Currently, one of the oldest and most common infectors of files is the
Jerusalem (1813) virus. All disinfectors naturally claim to be able to
remove this virus. Yet the Jerusalem virus frequently overwrites part
of the original file (due mostly to its many bugs) making it impossible
to restore the infected program. In spite of this, most (if not all)
disinfectors claim to disinfect Jerusalem infected files. A very
dangerous situation! I'd like to stress that:
IT IS TOTALLY UNSAFE AND IRRESPONSIBLE TO DEPEND UPON
DISINFECTORS AS A WAY TO RECOVER FROM VIRUS INFECTIONS.
INTERCEPTORS
Interceptors (also known as resident monitors) are particularly useful
for deflecting logic bombs and trojans. The interceptor monitors
operating system requests that write to disk or do other things that the
program considers threatening (such as installing itself as a resident
program). If it finds such a request, the interceptor generally pops up
and asks you if you want to allow the request to continue. There is,
however, no reliable way to intercept direct branches into low level
code or to intercept direct input and output instructions done by the
virus itself. Some viruses even manage to disable the monitoring
program itself. It is important to realize that monitoring is a risky
technique. Some products that use this technique are so annoying to use
(due to their frequent messages popping up) that some users consider the
cure worse than the disease! An interception (monitoring) product would
be a useful adjunct to a data integrity program, as protection against
some the more simple minded logic bombs.
INOCULATORS
There are two types of inoculators or so-called "immunizers." One
modifies files or system sectors in an attempt to fool viruses into
thinking that you are already infected. The inoculator does this by
making the same changes that the viruses use to identify the file or
sector as infected. Presumably, the virus will not infect anything
because it thinks everything is already infected. This works only for
a very small number of viruses.
The second technique is actually an attempt to make your programs
self-checking by attaching a small section of check code onto your
programs. When your program executes, the check code first computes the
check data and compares it with the stored data. It will warn you if it
finds any changes to the program. Not only can this be circumvented by
existing stealth viruses, but the self-checking code and check data can
be modified or disabled as well. Another problem arises because some
programs refuse to run if they have been modified in this way. This
also creates alarms from other anti- virus programs since the attached
self-check code changes the original program in the same way a virus
would. Some products use this technique to substantiate their claim to
detect unknown viruses.
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INTEGRITY CHECKERS
Integrity check based products work by reading your entire disk and
recording integrity data that acts as a signature for the files and
system sectors. An integrity check program is the only solution that
can handle all the threats to your data along with viruses. Integrity
checkers also provide the only reliable way to discover what damage a
virus has done. A well-written integrity checker should be able to
detect any virus, not just known viruses.
So, why isn't everyone using an integrity checker? Well, until
recently, there hasn't been an integrity checker available without some
significant drawbacks. In fact, many anti-virus products now
incorporate integrity checking techniques. One problem with many
products is that they don't use these techniques in a comprehensive way.
There are still too many things not being checked. Some older integrity
checkers were simply too slow or hard to use to be truly effective. A
disadvantage of a bare-bones integrity checker is that it can't
differentiate file corruption caused by a bug from corruption caused by
a virus. Only recently have advanced integrity checkers (e.g.,
Integrity Master) become available that incorporate the smarts to
analyze the nature of the changes and recognize changes caused by a
virus. Some integrity checkers now use other anti-virus techniques
along with integrity checking to improve their intelligence and ease of
use.
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If you choose an integrity checker, be sure it has all these
features:
o It's easy to use with clear, unambiguous reports and built-in help.
o It hides complexity, so that complicated details of system file or
system sector changes are only presented if they present
information the user must act upon.
o The product recognizes the various files on the PC so it can alert
the user with special warnings if vital files have changed.
o It's fast. An integrity checker is of no use if it's too slow to run.
o It recognizes known viruses, so the user doesn't have to do all the
work to determine if a change is due to a software conflict, or if it's
due to a virus.
o It's important that the integrity computation be more sophisticated
than a mere checksum. Two sectors may get reversed in a file or
other damage may occur that otherwise rearranges data in a file. A
checksum will not detect these changes.
o It's comprehensive. Some integrity checkers, in order to improve
their speed, don't read each file in its entirety. They read only
portions of larger files. They just spot check. This is unacceptable
-- it's important to know the file hasn't changed, not just that some
of the file hasn't changed.
o It checks and restores both boot and partition sectors. Some
programs check only files.
(Fortunately, Integrity Master does all these things.)
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GADGETS
There are currently some gadgets (hardware devices) that are sold as
virus protection. So far, I haven't seen anything that provides
protection beyond what is offered by software-only products. Beyond
putting some of the anti-virus code in read only memory (ROM), I've seen
little that can be accomplished by existing hardware. In one product,
the hardware was used to store some integrity data; a floppy disk can do
the same thing and it's actually more secure.
PREVENTION:
Hardware techniques, such as placing all your programs in read only
memory (ROM), can, in theory, provide virus prevention, but nothing even
comes close to doing this yet. Pure software techniques can probably
not prevent all viruses. There are all sorts of schemes that make it
more difficult for a virus to penetrate your system, but none totally
eliminate the threat of a virus. For each software-based technique,
there is a way a virus could circumvent it. Software helps a lot, but
isn't absolute protection. While prevention of viruses may not be
possible, detection is. Detection, if applied carefully, can detect all
viruses, no matter how tricky. If viruses are detected before they
spread, the most serious aspect of the virus threat is eliminated. If
integrity checking (detection) is practiced widely, the threat of a
virus spreading to millions of PCs and then years later doing a
destructive act can be eliminated.
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CHAPTER THREE - VIRUS MYTHS
____________________________________________________________________
MYTHICAL SOURCES
Attachment to a network or BBS
Simply being attached to a network (such as CompuServe, or
Internet), a bulletin board system (BBS), or even a local area
network (LAN) will not make you susceptible to viruses. The only
way you can get a virus is to execute a program on your PC that
you obtained over the network. The mere act of downloading the
program is harmless; it's only by downloading and then executing
an infected program that your PC can become infected. I hope it's
clear that the mere act of reading electronic mail cannot infect your
PC.
There is one thing that can happen though. If you have the device
driver ANSI.SYS (or an equivalent) loaded (in your CONFIG.SYS
file), someone could send a sequence of characters to your screen
(ANSI sequence) that assigns a set of key strokes to a key on your
keyboard. These keystrokes could easily be something harmful like
"DEL *.*". When you hit the key that was reassigned, the
command would execute just as if you had typed it yourself. This
"practical joke" could cause some trouble, but it certainly can't
reproduce and isn't a virus.
From Data
Since data is not executed, you cannot become infected from data.
If someone sent you a data file that contained a virus, you would
have to rename the file and then execute it to become infected!
You can, however, become infected from a diskette that is not
bootable and contains no (apparent) programs. The explanation for
this is that all diskettes have a boot sector that contains a program
that can become infected by a boot sector virus. If you leave such
an infected diskette in your drive when you power up or boot, your
PC will be infected!
From CMOS Memory
PC AT (80286 and 80386 based) type computers and later models
contain a small amount of battery backed CMOS memory to store
the configuration and to maintain the time and date. This memory
is never executed, so although it could be damaged by a virus, you
can never become infected from CMOS memory.
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QUICK AND EASY CURES
I've discussed the various approaches to the virus problem, and
you've no doubt seen that there are no instant cures for viruses, yet
many products make claims that they can't quite support. Everyone
would like to just buy product X, run it, and be rid of viruses forever.
Unfortunately there is no such easy cure.
SILLY TRICKS
There have been many articles and books written by various virus
"experts" that propose doing all kinds of things to virus proof your PC.
Here are some of the tricks that I consider most widespread and most
useless:
Write-protecting Your Files
You can use the DOS ATTRIB command to set the read only bit on files.
This is so easy for a virus (or any program) to bypass, that it simply
causes far more problems than it cures.
Hiding or renaming COMMAND.COM
COMMAND.COM is a program that executes each time you boot your PC.
There was an early virus that only infected COMMAND.COM, so the idea
of hiding or renaming this file began. Today, many viruses actually
go out of their way to avoid infecting this file, since some
anti-virus products single out this file and a few others for special
scrutiny. With today's viruses, hiding COMMAND.COM is utterly futile.
Checking Time and Date Stamps
While it's helpful to check the time and date stamps of your
executable files for unexpected changes, this is not a reliable way to
catch viruses. Many viruses are smart enough not to change the time
and date stamps when they infect a file. Some viruses even hide the
change to a file's size when they infect a file.
CERTIFIED SOFTWARE?
It's the policy in some companies to have a certification desk where all
software executed on PCs must be checked out. The person at the
certification desk usually runs the software through an anti-virus
product to check for known viruses and then sets the date ahead on the
PC and checks for anything strange. If all looks OK, the software is
certified clean. This is actually a reasonable idea. The danger comes
from the "certified clean" label. As we've seen in our discussion of
virus triggers, simply setting the date ahead is not a reliable way to
set off most virus triggers. The hazard comes from people taking the
"Certified clean" label too seriously. It's just not
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possible to know for sure that any piece of software doesn't contain a
virus. An unknown virus could be lurking that simply hasn't triggered
yet. If the virus screening desk should get such a virus, they could
easily spread the virus to all other disks that they are certifying
clean!
RETAIL SOFTWARE ONLY?
Several "virus experts" have suggested that users avoid downloading
software and avoid shareware. There are no facts to support this
viewpoint. The most common viruses are boot sector viruses such as
Stoned and Michelangelo that spread when someone boots from an infected
disk. To spread these viruses, a physical disk must be passed around and
then booted. Michelangelo spread widely because software distribution
disks were infected with this virus. There was no reported incident of
this virus spreading via shareware. It is, of course, wise to make sure
that you download your software from a source that screens each program
for known viruses. You are actually more likely to be infected from
software purchased at a retail outlet than from shareware. Quite a few
viruses have been shipped directly from the software manufacturer in the
shrink wrapped packages. One major software company has on at least two
separate occasions shipped a virus with their product. Buying shrink
wrapped retail software is much more dangerous than many people think it
is, since many retailers accept returned software and then simply rewrap
the software and sell it again. This software could have easily been
infected by the first user who tried it and then returned it.
WRITE-PROTECTING YOUR HARD DISK
There are several programs that claim to write-protect your hard disk.
Since this is done in software, it can be bypassed by a virus. This
technique, however, will stop a few viruses and will protect your disk
from someone inadvertently writing to it. These programs are generally
less effective than the virus interception products.
It IS possible to write-protect a disk using hardware, but this does not
seem to be readily available.
VIRUSES ARE THE BIG THREAT?
As we've seen in examining the other threats to the integrity of your
data, viruses are among the less likely threats that you face. Don't
protect yourself against viruses and ignore the other threats!
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SAFE COMPUTING (SAFE HEX?)
You may have heard this rumor: "You don't need an anti-virus product,
just backup your disk regularly and keep an eye on your programs."
Yes, it is vital to have good backups, but that is no longer enough.
You may also have heard that provided you don't share programs or
download (practice "safe hex"), you have nothing to worry about. This
is no longer sufficient protection; every time you buy a software
package you are exposing yourself to virus infection. It is not
possible to be safe from viruses by secluding your PC!
There are now some very sophisticated viruses that can do considerable
damage. The worst ones damage your files slowly so even your backups
may be useless unless you detect the damage before it's too late.
Although viruses may not be very likely to attack your system when
compared to other threats, they do represent a very real and very
dangerous threat -- a threat you cannot ignore or combat merely with
good backups, seclusion or common sense.
SOFTWARE IS USELESS AGAINST VIRUSES
Maybe we should just surrender to viruses and wait for a fool-proof
hardware solution? Viruses can defeat any software defense -- right?
Wrong! The viruses are playing on your turf, so you have an advantage.
By cold booting from a good copy of DOS on diskette, you can bring up a
clean operating system (DOS) and then use an integrity checker to look
for any unexpected changes. A virus will betray itself in the system
sectors or executable files.
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CHAPTER FOUR - VIRUS REALITIES
____________________________________________________________________
THE ONLY REAL SOURCE OF VIRUSES
You can't get a virus merely by being connected to a network or
bulletin board system (BBS).
There is only one way you can get a virus and that's to execute a
program containing a virus. Period. End of story. Well, almost the
end of the story. What some people don't know is that every disk and
diskette has a program on it, even if it appears empty. This program is
in the boot sector. Most people don't think of boot sectors as programs
or perhaps even know that boot sectors exist. If you leave a data
diskette in your A drive and boot your PC, you could be executing an
infected program in the boot sector, thereby infecting your PC with a
virus. Make sure you NEVER boot from a diskette unless it's a known
good copy of DOS.
SHAREWARE IS AS SAFE OR SAFER
There is no reason to avoid shareware. If you want to get the latest
anti-virus software, it's easiest to get it as shareware since you are
buying directly from the author. Shareware does not have to go from the
author to the publisher, then through the distribution chain before it
even gets to sit on the shelf. Who knows how long your retail package
has been on that shelf?
FEW VIRUS FREE PROGRAMS
Unfortunately, there is no way to look at a program (unless you wrote
the program yourself in assembly language) and positively declare
there's no virus in it. All you can say is that the program contains no
known virus. You never know what may be lurking inside of a program
waiting for just the right trigger to begin infection or perhaps an
attack.
While you can't be sure of detecting a virus while it's inert inside a
program, you definitely CAN detect it as it infects or attacks your
files. The changes which must be made by a virus can always be detected
with the appropriate software.
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OTHER CAUSES MORE LIKELY
Viruses are not the greatest threat to your data, so let's not forget
about the other threats too.
WRITE-PROTECTING FLOPPIES
While write-protecting your files and your hard disk is of questionable
value, you definitely CAN write-protect your floppy disks. Just cover
the notch on the 5.25 inch diskettes, or on 3.5 inch diskettes, slide
the little tab to expose the hole. The only risk here is that some
diskette drives may be defective and still allow writing on the
diskette. If in doubt, do a test and check out your drive.
BEWARE THE CE AND THE DEMO!
According to our reports, one of the major sources for infections is the
customer engineer (CE) or repairman. The CEs frequently carry
diagnostic diskettes with them when they go from PC to PC on service
calls. It's all too easy for these diskettes to become infected. Sales
people doing demos on various PCs are also very susceptible to getting
their demo diskettes infected.
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CHAPTER FIVE - WHAT TO DO?
SOME SUGGESTIONS:
____________________________________________________________________
ACTION IS VITAL - NOW!
Too many people wait for a virus to attack their PC before they take any
action. Once a virus reveals its presence on your PC, it may be too
late to recover damaged files. There are many viruses that cannot be
successfully removed due to the way the virus infects the program. It's
absolutely vital to have protection before the virus strikes.
It's vital that you protect against all threats to data integrity, not
just viruses. All threats to data integrity are much easier to deal
with if they are detected as early as possible. If you wait until you
notice that your hard disk is losing data, you may already have hundreds
of damaged files.
BACKUP POLICY
It's essential to carefully protect all your software and regularly
backup the data on all your disks. Do you have a single disk that you
can afford NOT to regularly backup? It's rare to find any PC that does
not have some type of important data stored on it.
SUGGESTED BACKUP POLICY:
1) All original software (program) diskettes should immediately be
write-protected, copied and stored in two secure, separate, locations
after installation. If you are using an integrity check program,
immediately record (initialize) the integrity data for the new
programs after installing.
2) Determine a schedule for full backups by considering how frequently
your data changes. It is an excellent idea to have three full sets of
backup tapes or diskettes and to store one set at another location to
protect against fire, theft, or some other disaster. If your data is
critical, you may wish to have a separate cycle of backups (e.g.,
quarterly or yearly) that can be used to recover when someone damages
(or deletes) a vital file, but the deletion isn't discovered until
months later.
3) The full backups should be coordinated with periodic incremental
backups. The incremental backup, which copies just the files that
have changed, normally runs very quickly and takes just a minute or
so. Many people find that an incremental backup run at the end of
each day works quite well. This way their data is protected should
anything happen overnight.
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4) Make sure you use reliable backup hardware and software.
Periodically test by restoring from a backup. Too many people
have discovered that their backup program couldn't recover their
files when it was too late. If you use an integrity check program
you can verify that the restored files are correct.
INTEGRITY CHECKING POLICY
Each PC which has data that you can't afford to lose or have corrupted
should have a schedule of regular integrity checking, similar to the
backup schedule. By doing once a week full integrity checks, you can
stay one step ahead of any trouble. By doing a quick update of your
integrity data on a daily basis, you can stay aware of exactly what
changes on your PC and why. This way if you start to encounter a
software conflict, a failing hard disk, or a virus, you'll be able to
quickly differentiate the unusual changes from the usual ones.
Whenever you install new software, immediately record the integrity data
for those programs, so that any future infection or damage can be
detected.
Whenever you copy programs, check that the new programs are exact copies
of the originals. The easiest way to do this is to always copy
integrity data along with the programs. You can also use any integrity
checker, checksum program, CRC program, cryptographic signature program,
or even the DOS COMPARE utility to verify that you made good copies. Do
this check only when you know no virus is in control of your PC;
therefore, it's best to cold boot from a write- protected floppy to
verify your program copies are good.
If you have diagnostic software, plan to run it at intervals. If you
leave your PCs turned on at night, why not leave them running
diagnostics?
RUN CHKDSK
Run CHKDSK (or some equivalent program) regularly on each PC, and pay
attention to the results. If you are seeing problems, be sure you
understand what's causing the problems. If you are experiencing
cross-linked or lost clusters, something is being damaged. Run an
integrity checker to find out exactly what is being damaged. Also pay
attention to the amount of available memory. If this suddenly changes
with no new resident (TSR) software installed, you may have a virus.
DETERMINING CAUSES OF CORRUPTION
It's not a question of "if" but a question of "when"; all too soon you
are going to encounter a damaged file (a file that has changed for
unknown reasons). How can you discover what caused the damage? o First
gather as much information as possible. Did you do anything unusual?
Did you install any new software? Did you execute any programs that you
don't normally use? Have you seen any signs of hardware problems? (See
the section following on signs of hardware problems).
Integrity Master (tm) - 79 - Data Integrity and Viruses
o Run CHKDSK to see if your directories and other areas are OK.
o Run a full integrity check to see if anything else has changed.
o If you suspect hardware problems as the culprit, then run any
diagnostic programs you have. If the diagnostics don't turn anything
up, but you still suspect a hardware problem, then run your integrity
check in full check mode daily for a while. This should help track
down exactly what's happening on your PC.
o If you suspect software problems, run the software in question and
then run your integrity check to see if anything is being corrupted.
When doing this, it's very helpful to duplicate the original situation
of the problem as closely as possible. Make sure the hardware is the
same and that you have exactly the same resident programs and device
drivers loaded as when the problem first occurred.
o Could the problem be a virus? If you think so, have you seen any of
the signs of virus activity listed in the next section? Are only
executable files (such as files ending in .EXE, .COM, .OVR, .OVL .BIN,
or .SYS) affected? If so, how many? If more than one or two
unrelated program files have mysteriously changed, it could likely be
a virus. Remember that some programs (such as Wordstar and SETVER)
modify themselves as part of normal execution. If the programs have
changed but the DOS time and date stamps haven't, this is further
reason to suspect either a serious problem or a virus. If you are not
using an advanced integrity checker (such as Integrity Master) that
recognizes known viruses, you may wish to get a virus scanner at this
point to see if you have a known virus. If this turns up nothing,
then it's time to play detective - you may have discovered a brand new
virus (lucky you!). Please see the section in Chapter Six on Playing
Detective.
EDUCATION
One very important thing that you can do to assure the integrity of the
data on your PCs is to educate everyone who uses a PC. It's vital that
they understand how to backup their files and which files normally
change on their PC and which ones don't. If you can teach them to
understand the output of a thorough integrity check program, then you'll
be able to sleep at night knowing that all is well with your PCs! Even
lacking an integrity check program, it's vital that everyone be aware of
what problem signs to look out for. This way the more dangerous threats
to data integrity will not go unnoticed.
Integrity Master (tm) - 80 - Data Integrity and Viruses
SIGNS OF HARDWARE PROBLEMS
Watch out for recurring error messages that the disk is not ready when
you try to boot the PC. If you periodically experience any type of
disk-error message, or if disk accesses seem to be getting consistently
slower, you may be experiencing the beginning of a serious disk problem.
SIGNS OF SOFTWARE PROBLEMS
These symptoms could reveal software conflicts or bugs:
o CHKDSK reporting problems.
o A file that was just processed by a program (such as a spread sheet)
is damaged or unreadable by the program but you can copy the file
with no error messages.
SIGNS OF VIRUSES
These symptoms may betray the existence of a virus:
o Disk activity when there should not be any activity. (Some disk
caches cause this to happen normally.)
o Programs taking longer to load but the disk drive appears to be
healthy.
o Any unexplained behavior on the PC such as music, bouncing balls,
black areas on the screen, falling letters, weird messages, or
unexplained slowdown of the PC.
o Less total or free (available) memory on your PC (use CHKDSK or
MEM). This should change only when you add new resident
programs or device drivers. Note, most PCs have 655360 total
bytes of memory but certain models (i.e., some PS/2s) reserve a
thousand bytes of high memory.
o Unexplained bad spots on your disk or fewer total bytes (as
reported by CHKDSK).
o If you find extra executable files (e.g., ".COM" files) showing up,
you may have a companion style virus.
Integrity Master (tm) - 81 - Data Integrity and Viruses
RESPONSIBILITY
If you are in a larger organization, it's crucial that someone has the
responsibility for assuring data integrity. The first task facing this
person would be to assure that all important data is backed up and that
all users are educated with respect to normal operation of their PC.
The next step would be to start a regular program of integrity checking.
POLICY AND ROUTINE
The procedures for backing up and checking the integrity of critical
data cannot be left to word of mouth, but should be clearly explained
in a written set of procedures. Data integrity is too important to leave
to chance. If this isn't done, guess what gets put on the back burner
(in other words: not done), when people get busy? (Who isn't busy?).
Some recommended procedures:
o Never leave a floppy disk inserted in a drive longer than necessary.
Remove all diskettes immediately. This reduces the chance of
inadvertently booting from the diskette and picking up a boot sector
virus.
o Check the integrity of all files after installing new software or
copying programs.
o If a stranger (such as a sales or repair person) runs software on a
PC, do a full integrity check immediately afterwards.
o Immediately write-protect and backup all diskettes containing
software.
o Schedule regular incremental and full backups.
NETWORKS AND VIRUSES
Make sure that any shared executable files allow only execute or read
access. Execute only is best, but it's essential not to allow write
access. Most network compatible programs allow you to store the files
they write to on separate disks from the programs themselves. Be sure to
limit write access with access rights not with file attributes (Netware
FLAG or FLAGDIR). A virus can easily bypass file attributes, but access
rights can thwart the virus's attempts to write to the shared disk. The
person who supervises the LAN needs to have two accounts -- one
privileged and one not. For normal use, they should use the less
privileged account. The privileged account should be used only when the
job requires supervisor rights. It's critical that any user with
supervisory rights log off as soon as possible and never execute any
other programs, especially those on a workstation.
Integrity Master (tm) - 82 - Data Integrity and Viruses
Run regular integrity checks on the file server. This is important on
the workstations too, but is critical on the file server since an
infected file here could quickly infect all the workstations on the
network.
Never access an unchecked workstation with network administrator
(supervisor) authority!
GUIDELINES FOR USING ANTI-VIRUS PRODUCTS
Most modern anti-virus products use a combination of the techniques I
just mentioned. Unfortunately, most products still get almost all of
their protection from their scanner component. It's vital to understand
exactly how your product works so that you understand what type of
protection you really have. Here are some rules that will help you make
sure that you get maximum protection out of whatever product you already
have:
o Be sure to cold boot your PC from a write-protected diskette before
virus checking. Most anti-virus products make this
recommendation, but this rarely gets done because the
recommendation is often buried in some obscure location in the
documentation. If your PC is infected with a virus that your
scanner does not recognize, you could infect all the programs on
your disk. Don't take this chance; boot from a write-protected
diskette before you scan.
o If you are using a product which depends mostly on its scanner
component, make sure that you always have the latest version.
Scanners are often updated every 30 days.
o Before you execute or install any new software, check it first. If it
comes with an install program, check again after you install the
software; an install program will frequently change or decompress
executable programs. After you first execute brand new software
do an additional check of your system to make sure everything is as
it should be.
o If your product contains a scanner component, consider checking
the boot sector on all diskettes brought in from another location --
EVEN DATA DISKETTES! Inevitably someone will leave these
diskettes in their A drive, potentially spreading a boot sector virus.
Integrity Master (tm) - 83 - Data Integrity and Viruses
CHAPTER SIX - HANDLING A VIRUS ATTACK
____________________________________________________________________
DON'T PANIC
Don't do anything rash if you suspect a virus attack. Be skeptical,
there are quite a few practical joke programs that behave exactly like
viruses. There's even a virus simulator that simulates the Ping Pong
(bouncing ball), Jerusalem (black hole), Cascade (falling letters on the
screen), Yankee doodle (music) and a few other viruses. It's perfectly
harmless, but it has alarmed many people. Don't do anything drastic
until you confirm that it really is a virus.
REPORT THE ATTACK
Report the virus attack to the police or to a virus researcher or anti-
virus developer. We need to stop sweeping this under the rug. If we
can track where viruses first get started, then maybe we can apprehend
the culprits who are writing and distributing these things.
PLAY DETECTIVE
It is very important that you track down how you got the virus. If you
got it from someone's software, it's vital that they be notified. The
sooner these viruses are detected, the less damage they can do.
Suppose you have indications of a virus, but your software doesn't
identify it as a known virus. What do you do? First, cold boot (hit
the red reset button or power off and back on) from a known good
write-protected copy of DOS on a diskette. Run a full integrity check.
Run CHKDSK and print the results. Now execute any suspect programs.
Execute them several times. Viruses may wait for some trigger event to
begin infection. Run CHKDSK again to see if the amount of free memory
has been reduced. This is a sign of a virus going resident in memory.
Now cold boot again and rerun an integrity check. Repeat this cycle
with the various suspect programs. This should track down the guilty
program if you've got one. Keep in mind that if it's a virus, it will
modify other programs and those programs should themselves further
modify other programs. By executing the modified programs, it's possible
to tell whether you really have a virus or you just have a buggy program
that is accidentally writing to other programs.
Integrity Master (tm) - 84 - Data Integrity and Viruses
CLEAN HOUSE
Follow these steps when removing a virus from your PCs:
o Cold boot (Power off and on or hit the reset button) from a known
good write-protected copy of DOS.
o Delete all infected files.
o Reload any infected system sectors. If you do not have a utility to
reload the DOS boot sector, you can use the DOS "SYS" command
after cold booting from a write-protected diskette (e.g., "SYS C:").
o Rerun a full integrity check, or at least a scan if you don't have an
integrity checker.
o Check any floppies that may have been infected. Remember, if you
have a system sector virus such as Stoned, Joshi or Brain, even
empty data diskettes can be infected. Check them all.
o Notify any other PC user you have contact with to check their PCs.
GUARD THE HOUSE
Virus infections return in a very high number of cases. This is usually
because somewhere there is an infected file or diskette that was missed
in the first cleaning. Run your integrity checker or anti- virus
program daily, for the next month, to catch a possible repeat infection.
Integrity Master (tm) - 85 - I N D E X
4096 virus, 59 Copying programs, 23, 78
Abandon changes, 44 Corruption, 8, 21, 24, 27, 32, 36,
Abort, 44 38, 51, 52, 56, 68, 78
Advanced Option Menu, 18, 35, 44 Counting viruses, 60, 76
Algorithms, 16, 32 Critical error, 28
Alternate colors, 13 Cross-linked clusters, 51, 64, 78
ALTernate key, 21 Cryptographic signatures, 9, 16
Alt/X, 20 Current and Lower directories, 17
ANSI.SYS, 71 Current diRectory only, 17
APPEND, 10 Current option settings, 36
ASSIGN, 10 Customer engineer (CE), 76
Attack phase, 22, 56 Customizing, 35
Automatic video mode, 13, 30 Data integrity, 9, 27, 51, 53, 64
Auto-named report file, 18, 19, 29 Data recovery tools, 52
Backup, 63, 64, 74, 77, 79, 81 Date stamp, 9, 29, 39, 72, 79
Bad clusters, 58 Deleting files, 64
Badly damaged disks, 19 Demo diskettes, 76
Batch files, 30, 32 Descendant directories, 17
BBS, 71, 75 Destroying viruses, 26
BIOS, 53, 54, 68 Detecting unknown viruses, 24
Bitnet, 1 Detecting viruses, 23
Boot sector, 17, 19, 43, 57, 58, Device number, 19
69, 71, 75, 81, 82 Diagnostic programs, 9, 27, 63, 64,
Brain virus, 58, 84 78, 79
Bugs, 53 Directory change, 20
Bypass memory check, 26, 46 Dir-2 virus, 58
Cascade virus, 25, 83 Disinfection, 25, 26, 66
Certified software, 72 Disk change, 20
CGA, 39 Disk errors, 9, 27, 28, 32, 43, 47,
Change history, 18 52, 63, 80
Change management, 8, 29 Disk failure, 16, 19,52, 63, 78
Change menu, 41 Disk letters, 43
Changes to executable programs, 24 Disk space, 30
Check disk for known viruses, 18, 23 Downloading, 71, 73, 74
Check menu, 48 Education, 79
Check values, 32 Electronic mail, 1, 71
Checking specific files, 17 Encryption, 9, 16, 43, 68
Checksum, 69 Entire disk integrity,15, 17, 23, 27
CHKDSK, 51, 53, 58, 64, 78, 80, 83 Error levels, 32
Cluster viruses, 26, 59 Error recovery, 19, 47
CMOS, 15b, 71 Errors, 32
Cold boot, 22, 24, 26, 27, 46, 48, ESCape, 21, 44
82, 83, 84 Evaluation, 11
Cold booting, 82 Example report, 28
Colors, 13, 35, 47 Exclude menu, 39
Command line, 13, 18, 26, 30, 35, Excluding directories or files, 39
38, 46, 47 Executable files, 18, 23, 24, 37, 38,
Commands menu, 20 38, 45, 48, 55, 58, 68, 71, 72,
COMMAND.COM, 72 74, 77, 79, 81
Common Questions, 47 Exit, 43
Companion viruses, 22, 26, 39, 59, Explanation of the display, 15
80, Extend disk life, 27
Configuration, 43 F1 (help), 14, 15
Control card, 30, 31 False alarms, 26, 48
Copying IM files, 11 Fastest way to exit, 21
Integrity Master (tm) - 86 - I N D E X
File corruption, 8, 21, 24, 25, 27, 32Internet "virus", 54
36, 38, 51, 53, 56, 68, 78 Introduction, 51
Files on current Disk, 17 Intrusion protection, 64
Files to check, 37 Jerusalem virus, 25, 67, 83
Files to iNitialize, 23, 37 Joke, 64, 71, 83
Files (vital for IM), 12 Known viruses, 8, 9, 18, 25, 26,
Finger checks, 8, 52 46, 65, 69
Fixing your disk, 10, 63 LAN, 28, 33, 34, 71, 81
Full installation, 11 Laptop, 13, 30
Full integrity checking, 36, 78, Large disks, 10
79, 83, 84 LCD, 12, 13, 30
General virus checking, 46 License terms, 3, 33
Glitches, 51 Limitations, 10
Guided tour, 14 Logic bombs, 53, 67
Hardware configuration, 43 Logical disk, 19, 43, 57
Hardware errors, 47, 52, 80 Low level format, 27
Hardware problems, 27 LPT1, 19
Hardware protection, 63 Malicious damage, 52
Harmless viruses, 25, 56 Maltese Amoeba virus, 65
Help, 15 Master boot record, 18, 19, 43, 57
Help Index, 7 Maximum number of files, 10
Help menu, 14 Media coverage, 51
Hidden system files, 44 Memory check, 26, 46
Hiding IM.PRM, 29 Menus, 10, 14, 21
How viruses infect, 9, 21, 55 Minimum memory, 10
HPFS, 34 Miracle Infections, 59
Ignore Time/date changes, 39 Misleading results, 10
IMcheck, 44 Monitoring, 67
IMcheck license, 33 Monochrome mode, 13, 30, 47
IMCHECK.EXE, 32, 33 Multiple parameter files, 31, 35
IMprint, 47 Multiple sets of options, 31, 35
IMPROC.TXT, 12, 13, 22, 23, 32, 42 Music, 22, 25, 56, 80, 83
Imview.exe, 47 Mutating virus, 60
IM.EXE, 12, 32 Mutation engine, 59, 60
IM.PRM, 12, 13, 29, 35, 43 Networks, 28, 54, 71, 75, 81
Infection phase, 55 New viruses, 24
Initialize, 46 No halt, 30, 38
Initialize menu, 23 Nonstop execution, 30, 31, 38
Initializing integrity data, 15 Norton utilities, 52, 58, 63, 64
Installing new software, 23, 78, Only changes reported, 39
79, 81, 82 Open fail, 28
Instructions, 10 Open files, 28
Integrity Advisor,10, 12, 22, 41, 42 Option settings, 13
Integrity checking, 22, 36, 68, 69, Options menu, 18, 22, 23, 35
70, 74, 78, 81 OS/2, 28, 33, 34
Integrity data, 9, 15, 16, 20, 21, Overlays, 18, 48, 59
22, 23, 28, 29, 35, 36, 37, Parameter file, 12, 13, 29, 30, 35,
39, 40, 42, 43, 68, 77, 78 36, 43
Integrity data file names, 23, 42 Parameters, 30, 32
Integrity data location, 21, 43 Partition sectors, 18, 19, 43, 57,
Integrity data off-line, 43 58, 64, 69
Integrity initialize, 9 Partition table, 57
Interceptor, 54, 67 Pause (P) key, 38
Intermittent problems, 27, 63 Pausing, 37
Internet, 1 Physical disk drive, 19, 43, 57
Integrity Master (tm) - 87 - I N D E X
Plan for day-to-day use, 12 Shareware, 73, 75
Pogue virus, 60 Shelling to DOS, 20, 47
Policy, 81 Short-cut install, 11
Polymorphic viruses, 59 Signatures, 16, 28, 32, 68, 72
Power faults, 52 Silly tricks, 72
Printed output, 19 Software Attacks, 53
PRN, 19 Software problems, 53, 79, 80
Probability of file damage, 8 Solving problems, 47
Procedure for running IM, 22 Sound, 38
Procedures, 81 Source programs, 38, 45
Program changes, 26 Space (disk), 30
Programs, 22, 23, 24, 37, 38, 45, Spawning virus, 59
48, 55, 57, 70, 71, 75, 77, 78, Special characteristics, 9
QUESTION.TXT, 47 Speed, 10, 24, 29, 46, 69
Quick evaluation, 11 Statistics Summary, 21
Quick Install, 11 Stealth, 56, 58, 68
Quick integrity update, 22 Stoned virus, 56, 60, 84
Quick Update, 29, 36, 78 SUBST, 10
Quit, 44 Suggestions, 77
Read fail, 28 Surge protectors, 63
README.DOC, 12 Syntax, 30
Reinstall, 13 SYS command, 57
Reload data, 20 System files, 44
Reload files, 16 System sector changes, 26
ReLoad menu, 19 System sector viruses, 9, 19, 24,
Reload Missing partition, 19 57, 58
Reloading system sectors, 15, 84 System sectors, 9, 10, 15, 17, 19,
Reminders Before Checking, 18 22, 57, 58, 65
Removal instructions, 25 Technical support, 47
Repair, 10, 63 Threats, 9, 21, 51, 53, 61, 73, 74,
Report, 28 76, 77
Report file, 18b, 19, 29, 31, 39 Trigger, 21, 53, 54, 55, 56, 83
Report screen, 15 Trojans, 54, 55, 67
Reporting viruses, 25 TSR, 53, 56, 78, 79
Requirements, 10 Tutorial, 7, 15
Resident monitor, 67 Two-color display, 12
Resident programs, 53, 56, 78, 79 Typos, 8, 52
Retail software, 66, 73, 75 Unattended processing, 31
ROM, 68, 70 Unauthorized changes, 22, 29
Safe computing, 74 Unknown viruses, 8, 11, 18, 22, 24,
Save changes, 43 68, 73, 79, 83
Saving option changes, 35, 43 Unreadable data, 64
Scanning, 9, 18, 23, 30, 39, 59, Unusual video adapters, 12
60, 65, 66, 79, 82 Update hardware configuration, 43
Screen colors, 13, 35, 41 Variably named integrity data, 42
Screen layout, 15 Video adapter, 12, 13
Screen report, 39 Video mode, 13, 47
Scrolling, 37, 38
Sectors, 57
Security, 8, 29, 64
Self-check, 68
Self-modifying programs, 79
SetupIM, 7, 11, 12, 13, 14, 16, 18,
22, 29, 35, 41, 43, 44
SETUPIM.EXE, 12
Integrity Master (tm) - 88 - I N D E X
Virus Virus
checking, 18, 35, 45, 46 variants, 60, 61
checking procedure, 22 what is it, 54
companion, 22 Virus report, 25
damage, 15, 19, 22, 25, 27 Vital files, 12
Destroying, 26 Warranty, 3
Detecting, 23, 24 Whale virus, 60
detection, 32, 36 Why read, 8
infection, 19 Wild card characters, 40
infections, 21 Windows, 28, 33, 34, 48
known, 9 Worm, 54
names, 25 Write option changes, 35, 36
New, 24 Write protection, 68, 72, 73, 76,
removal, 25 77, 81
removing, 48
Reporting, 25, 26
resident, 22, 26, 46, 48
scanning, 9, 18, 23, 30, 39
Signs, 23, 38
symptoms, 25
system sector, 9, 19, 24
trigger, 21
unknown, 22, 24
variants, 25
what is it, 21
checking, 65
cluster, 59
collection, 61
companion, 59, 80
damage, 53, 56, 61, 66, 71, 74,
77, 83
defenses, 65
definition, 54
detection, 65, 68, 70, 75
experts, 54, 72, 73
how many, 60, 76
infection, 71
infections, 55, 58, 66, 84
known, 65, 69
multipartite, 58
mutating, 59, 60
myths, 71
new, 60, 79
phases, 55, 56
polymorphic, 59, 60
prevention, 70
removing, 66, 77
resident, 56, 66
scanning, 59, 65, 66, 79, 82
signs, 79, 80
stealth, 56, 58, 68
system sector, 57, 58
toolkits, 60
trigger, 54, 55, 56, 72, 83
unknown, 68, 73, 79, 83
Very nice! Thank you for this wonderful archive. I wonder why I found it only now. Long live the BBS file archives!
This is so awesome! 😀 I’d be cool if you could download an entire archive of this at once, though.
But one thing that puzzles me is the “mtswslnkmcjklsdlsbdmMICROSOFT” string. There is an article about it here. It is definitely worth a read: http://www.os2museum.com/wp/mtswslnk/