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1993-11-02
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NEUTER v01.01.00 (02 NOV 1993) -- checks for & removes the ASeXual V0.99 virus
Copyright (c) 1993, Professional Software Engineering
All Rights Reserved.
This program is for FREE distribution only.
A program to remove the ASeXual V0.99 virus from files. IT IS NOT INTENDED
TO DETECT AND REMOVE OTHER VIRUSES -- ONLY THE "ASeXual V0.99" VIRUS. This
program is very fast at what it does -- thousands of hard drive files can be
scanned in a single minute.
This program is a functional replacement for FINDV100 and FINDV110, which
are attempts to isolate the virus. This program positively identifies the
presence of the virus, and fully recovers from it.
NEUTER first reports whether the virus is in memory or not. If it is, the
program will terminate with instructions on how to properly go about removing
the virus -- you run the risk of spreading the virus just by running programs!
This program itself is immune to infection by the ASeXual V0.99 virus. If
the system does not have the virus in memory, the program will then scan for
all files in the given drive/directory specification and eradicate the virus
whenever it is encountered.
Legal Disclaimer
================
This program was produced and is provided FREE as a fix for a virus. The
author of this program makes no warranty that this program will fix your
problem, nor that this program will recover any or all of your data. It is
possible that certain circumstances may cause this program to erase
information. In no event can the author be held liable for damages resulting
from the use of this program. Every effort has been made to positively
identify a file as being infected with the virus before attempting to recover a
file from the virus.
This file should have come to you inside a PKZIP archive with authentication
that should have looked something like this:
-----------------------------------------------------------------------------
PKUNZIP (R) FAST! Extract Utility Version 2.04g 02-01-93
Copr. 1989-1993 PKWARE Inc. All Rights Reserved. Registered version
PKUNZIP Reg. U.S. Pat. and Tm. Off.
■ 80486 CPU detected.
■ EMS version 4.00 detected.
■ XMS version 3.00 detected.
■ DPMI version 0.90 detected.
Searching ZIP: NEU_0101.ZIP
Inflating: NEUTER.COM -AV
Inflating: NEUTER.DOC -AV
Authentic files Verified! # DQP160
Professional Software Engineering
-----------------------------------------------------------------------------
There should be only two files in the archive, and both should have the
authentication information. If not, check with the source you obtained this
file from.
Parameters:
A drive or path on the commanline to indicate where to start scanning for the
virus. A dot "." represents the current directory. All files will be checked,
reguardless of assumed file type. It will find and recurse into hidden
directories as well.
Examples:
NEUTER C: Disinfects the entire C: drive. Go boil a pot of tea
while you wait, it may take awhile.
NEUTER . Disinfects all files in the current directory, and all
directories underneath it.
NEUTER D:\UTILS Disinfects all files under the UTILS directory on D:
On exit, there will be a DOS errorlevel of 1 if the virus was encountered (in
memory or in a disk file), and 0 if not.
Release history:
v01.00.00 (01 NOV 1993)
* Original public release. Released the same day an infected file was provided
by ExecNet Information Systems for analysis. ExecNet Information Systems is
the author of the FINDV ("FindVirus") program.
v01.01.00 (02 NOV 1993)
* Determined that the stubfile for .EXE files could be infected by the virus as
a regular .COM file, since it does not pass the virus' "infected" check. Thus,
whenever a .COM file is cleaned, it is scanned a second time to insure that it
is not a stub. Improved the scanning process to pick up a few more complex
variants of the decryptor.
Virus characteristics:
======================
These characteristics were determined by actually examining the viral code, and
not by trial and error logging of changes to a system.
The ASeXual V0.99 virus is related to the Oƒƒspring series of viruses. It is
produced by the same author(s). It is not known which virus
Infected file date and times will remain unchanged. In the case of .COM stubs
for .EXE files, the information will be the same as for the .EXE file they are
stubbing, and the new .COM file will be hidden and readonly. It does not
infect COMMAND.COM or 0 byte files.
Virus is self-encrypting, and uses a cycle of register changes for the
decryption code (so the non-encrypted code is not consistent).
The growth of an infected file will range from +1673 to +1929 bytes. Each
sequential file infection increases the virus size by 1 byte until the max size
is reached, at which time the minimum size is used, and the process repeats.
Infections occur when programs are run, and 5 files will be infected (if you
run 5 programs (whether they are infected or not), 25 new files will be
infected). Note that some programs run others internally ("overlays"), and
these operations count as running a program as well. Also, whenever a disk
change ("Drive Select") is issued, the same infection sequence is triggered.
Note that many programs will perform disk select operations while they run
(say, to figure out what drive letters you have in your computer), and so
running a single program can easily tigger dozens of infection processes.
The virus takes over the DOS critical error handler when it goes to infect a
series of files, so if you have a write protected floppy in the drive, you will
not get an error message from DOS. Read-only files and hidden files are not
safe from the virus.
There are two special filenames in the program, and both appear to be
anti-viral data files:
CHKLIST.*
ANTI-VIR.DAT
Any time a program is run, the directory where the program is located is
checked for these two filespecs, and if they are found, they are made into 0
length files and deleted. It does not matter if they are hidden or readonly.
If the date is the 2nd day of any month, the virus message ("ASeXual Virus
V0.99 - Your computer has been artificially Phucked!") will be displayed to the
screen (via a DOS call -- which means that if the output of the infected
program was being redirected, you will not actually see the message), and if
you have a printer online, the screen will be repeatedly dumped to the printer.
There will be a beep between each attempted screen dump to printer, and a short
delay. The process will repeat (the virus text will not be redisplayed). The
keyboard LEDs will be flashing during this period, and any attempt to reboot
will fail, since the keyboard data is being manipulated by the virus. Because
there have not been reports of this virus in past months, it is probably safe
to infer that the virus is only about a month old as of this writing.
The virus appears to have bugs in it which cause it to lock up the computer
when certain infected programs are run. The .EXE stubs also do not work under
many conditions. It will also re-infect the .EXE stubs as if they were normal
.COM files, since they fail the internal check for infection that the virus
performs on a file.
The first time it is run within a system, it will load itself resident,
latching into the DOS INT 21h vector, waiting for programs to be run, and for
the current disk to be changed.
Thanks to the system operators at ExecNet Information Systems (they run the
ExecNet multi-line BBS) for originally isolating this virus, and providing me
with an infected file to create this fix. The ExecNet BBS is reachable at
(914) 667-4567 (modem), and is a distribution site for this program.
While this program is FREE, the author wouldn't turn down donations from anyone
who feels inclined to send him money for his work -- especially those who find
that this utility recovered their files from the virus. A number of hours went
into reverse-engineering the virus and developing a fix (and testing it), yet
the author did not develop this program out of a need to remove the virus from
his own equipment, which was never infected to begin with. If you feel like
sending a donation for my work, please make the cheque or money order (drafted
on a U.S. bank) payable to: "Sean B. Straw", and send it to the address below.
$5 to $10 is suggested IF YOU FEEL LIKE PAYING FOR THIS PROGRAM. You don't
have to.
Note that "FREE distribution" implies that you should not have paid ANYTHING to
anyone to get this program -- by the time a shareware diskette house gets this
program into production on floppies, McAfees SCAN and CLEAN programs should
have been updated with support for this virus. If you paid anyone money for
this program (other than the author), demand your money back, and if you get
the line "The $5.99 you paid was for the diskette and duplication", I would
heartily suggest checking out getting or using a modem (if you already have
one) -- a cheap 2400 baud internal would cost you less to buy than 8-10 such
shareware disks, though I'd recommend at least a 9600 baud modem. A modem will
open up a whole new world of computing to you.
While at this time I have no relationship with McAfee Associates, and they do
not support this program, they do have a fine line of software, including a
Virus scanner and disinfector. Their BBS number is (408) 988-5190
And if you were hit by the virus, you might consider seeing to it that you have
an updated version of whatever anti-virus package you normally use -- or you
should go buy a package to suit your needs.
About the author:
=================
Professional Software Engineering is a developer of system enhancement
utilities and a variety of anti-virus tools. We also provide custom systems
programming services in assembler and C, and perform password recovery for
files in PKZIP files which have been encrypted.
Professional Software Engineering
Post Box 2395
San Rafael, CA 94912-2395
(415) 459-7401