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              AUSCERT External Security Bulletin Redistribution
                             
         ESB-97.044 -- CIAC H-47 AOL4FREE.COM Trojan Horse Program
		       Destroys Hard Drives

                              17 April 1997

===========================================================================

CIAC has made available the following Information Bulletin concerning the
AOL4FREE.COM Trojan Horse Program. This program, when executed, can delete
all files under a DOS/WINDOWS environment.

As AOL4FREE.COM is a Trojan Horse Program and not a virus, it does not
spread on its own. It has to be run to cause any damage to the files on
the system.

Although the AOL4FREE.COM is different from the HOAX message that has been
circulating on the Internet, it can be attached to an e-mail message and,
if executed, may delete all files on the system.

The following security bulletin is provided as a service to AUSCERT's
members.  As AUSCERT did not write this document, AUSCERT has had no
control over its content.  As such, the decision to use any or all of this
information is the responsibility of each user or organisation, and should
be done so in accordance with site policies and procedures.

Contact information for CIAC is included in the Information Bulletin below.
If you have any questions or need further information, please contact them
directly.

If you believe that your system has been compromised, contact AUSCERT or
your representative in FIRST (Forum of Incident Response and Security
Teams).

Internet Email: auscert@auscert.org.au
Facsimile:      (07) 3365 4477
Telephone:      (07) 3365 4417 (International: +61 7 3365 4417)
	AUSCERT personnel answer during Queensland business hours
	which are GMT+10:00 (AEST).
	On call after hours for emergencies.


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CIAC INFORMATION BULLETIN

H-47: AOL4FREE.COM Trojan Horse Program Destroys Hard Drives

April 16, 1997 23:00 GMT
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PROBLEM:       A Trojan Horse program called AOL4FREE.COM that deletes all
               files on a hard drive is circulating the Internet.
PLATFORM:      DOS/Windows-based PCs
DAMAGE:        When the AOL4FREE.COM program is executed, all files and
               directories on the users C: drive are deleted.
SOLUTION:      DO NOT execute this program. If the program starts executing,
               quickly pressing Ctrl-C will save some of your files.
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VULNERABILITY  Users who download the trojaned AOL4FREE.COM program and
ASSESSMENT:    executes it will destroy all the files and directories on their
               DOS C: drive.
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NOTE: This is different from the AOL4FREE hoax message.

CIAC has obtained a Trojaned copy of AOL4FREE.COM that destroys hard drives.

CIAC has obtained a Trojaned copy of the AOL4FREE.COM program that, if run,
deletes all the files on a user's hard drive. If you are e-mailed this file,
or if you have downloaded it from an online service, do not attempt to run it.
If the program was received as an attachment to an e-mail message, do not
double click (open) it. Opening an attached program runs that program, which
in this case deletes all the files on your hard drive. The original
AOL4FREE.COM was a program for fraudulently creating free AOL (America Online)
accounts. Note that any attempt to use the original AOL4FREE.COM program may
subject you to prosecution.

NOTE: Most antivirus programs will not detect this or other Trojan Horse
      programs.

Detection
=========

AOL4FREE.COM is a Trojan program that is 993 bytes (2 sectors) long.
It masquerades as the AOL4FREE program that allows the fraudulent creation of
free AOL accounts. The following text is readable in the AOL4FREE.COM file
if you display it with the DOS TYPE command or the DOS EDIT program.

Compiled by BAT2EXEC 1.5
PC Magazine . Douglas Boling

Note that this text may appear in any program compiled with the BAT2EXEC
program and has nothing to do with the Trojan Horse.

If you open the AOL4FREE.COM file with a disk editor or with the Windows
Notepad program, the following text is found at the end of the second sector
of the file.

PATH
COMMANDC earc
/C C:
/C CD
DELTREE   /y *.*
ECHOOYOUR COMPUTER HAS JUST BEEN F***ED BY *VP* F*** YOU AOL-LAMER

Where F*** is a common vulgar explicative.

Recovery
========

Pressing Ctrl-C before the Trojan Horse finishes deleting all your files will
save some of them. If the program runs to completion, all the files on
your root drive will have been deleted. The files are deleted with the
DOS DELTREE command, so the contents of the files are still on your hard
disk, only the directory entries have been deleted. Any program that can
recover deleted files will allow you to recover some or all of the files
on your hard disk.

While attempting to recover files, be sure to not write any new files onto
the hard disk as the new files may overwrite the contents of a deleted file,
making it impossible to recover. You will probably have to boot your system
with a floppy and run any recovery programs from there.

If you happen to have one of the delete tracking programs installed on your
system (a program that keeps track of deleted files in case you want them
back) the recovery operation will be relatively simple. Follow the directions
in your delete tracking program to recover your files. If not, you will
probably have to recover each file individually, supplying the first character
of the file name, which is overwritten in the directory when the file is
deleted. Most DOS/Windows disk tools programs also have the capability for
recovering deleted files so follow the directions included with those programs
to do so.

Background
==========

The original AOL4FREE.COM program was developed to fraudulently create free
AOL accounts. The creator of that program has pleaded guilty to defrauding
America Online for distributing that program. Anyone else attempting to use
that program to defraud AOL could also be prosecuted.

An e-mail message was recently circulating about the Internet that warned of
an AOL4FREE virus, but that warning is either a hoax or a badly misunderstood
description of this Trojan Horse.
1.  This program is a Trojan Horse, not a virus. It does not spread on its own.
2.  A Trojan Horse must be run to do any damage.
3.  Reading an e-mail message with the Trojan Horse program as an attachment
    will not run the Trojan Horse and will not do any damage. Note that
    opening an attached program from within an e-mail reader runs that
    attached program, which may make it appear that reading the attachment
    caused the damage. Users should keep in mind that any file with a .COM or
    .EXE extension is a program, not a document and that double clicking or
    opening that program will run it.

CIAC still affirms that reading an e-mail message, even one with an attached
program, can not do damage to a system. The attachment must be both downloaded
onto the system and run to do any damage.
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For additional information or assistance, please contact CIAC:

    Voice:          +1 510-422-8193 (8:00 - 18:00 PST, 16:00 - 2:00 GMT)

    Emergency (DOE, DOE Contractors, and NIH ONLY):
                     1-800-759-7243, 8550070 (primary),
                                     8550074 (secondary)
    FAX:            +1 510-423-8002
    STU-III:        +1 510-423-2604
    E-mail:          ciac@llnl.gov
    World Wide Web:  http://ciac.llnl.gov/
    Anonymous FTP:   ciac.llnl.gov (128.115.19.53)
    Modem access:   +1 (510) 423-4753 (28.8K baud)
                    +1 (510) 423-3331 (28.8K baud)

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This document was prepared as an account of work sponsored by an agency of
the United States Government. Neither the United States Government nor the
University of California nor any of their employees, makes any warranty,
express or implied, or assumes any legal liability or responsibility for the
accuracy, completeness, or usefulness of any information, apparatus,
product, or process disclosed, or represents that its use would not infringe
privately owned rights. Reference herein to any specific commercial
products, process, or service by trade name, trademark, manufacturer, or
otherwise, does not necessarily constitute or imply its endorsement,
recommendation or favoring by the United States Government or the University
of California. The views and opinions of authors expressed herein do not
necessarily state or reflect those of the United States Government or the
University of California, and shall not be used for advertising or product
endorsement purposes.
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