Windows 2000 Default Permissions Could Allow Trojan Horse Program (Q327522)

-----BEGIN PGP SIGNED MESSAGE-----

===========================================================================
             AUSCERT External Security Bulletin Redistribution

           ESB-2002.603 -- Microsoft Security Bulletin MS02-064
     Windows 2000 Default Permissions Could Allow Trojan Horse Program
                                 (Q327522)
                             01 November 2002

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

        AusCERT Security Bulletin Summary
        ---------------------------------

Product:                Windows 2000
Vendor:                 Microsoft
Impact:                 Execute Arbitrary Code/Commands
Access Required:        Remote

- --------------------------BEGIN INCLUDED TEXT--------------------

- -----BEGIN PGP SIGNED MESSAGE-----

- - ----------------------------------------------------------------------
Title:      Windows 2000 Default Permissions Could Allow Trojan Horse
            Program (Q327522)
Date:       30 October 2002
Software:   Windows 2000
Impact:     Trojan Horse program execution 
Max Risk:   Moderate
Bulletin:   MS02-064

Microsoft encourages customers to review the Security Bulletin at: 
http://www.microsoft.com/technet/security/bulletin/MS02-064.asp.
- - ----------------------------------------------------------------------

Issue:
======
On Windows 2000, the default permissions provide the Everyone group
with Full access (Everyone:F) on the system root folder
(typically, C:\). In most cases, the system root is not in the search
path. However, under certain conditions - for instance, during logon
or when applications are invoked directly from the Windows desktop
via Start | Run - it can be. 

This situation gives rise to a scenario that could enable an attacker
to mount a Trojan horse attack against other users of the same
system, by creating a program in the system root with the same name
as some commonly used program, then waiting for another user to
subsequently log onto the system and invoke the program. The Trojan
horse program would execute with the user's own privileges, thereby
enabling it to take any action that the user could take. 

The simplest attack scenario would be one in which the attacker knew
that a particular system program was invoked by a logon script. In
that case, the attacker could create a Trojan horse with the same
name as the system program, which would then be executed by the
logon script the next time someone logged onto the system. Other
scenarios almost certainly would require significantly greater user
interaction - for instance, convincing a user to start a particular
program via Start | Run - and would necessitate the use of social
engineering. 

The systems primarily at risk from this vulnerability would be
workstations that are shared between multiple users, and local
terminal server sessions. Other systems would be at significantly
less risk: 

 - Workstations that are not shared between users would be at no
   risk, because the attacker would require the ability to log onto
   the system in order to place the Trojan horse. 

 - Servers would be at no risk, if standard best practices have
   been followed that advocate only allowing trusted users to log
   onto them. 

 - Remote Terminal server sessions would be at little risk,
   because each user's environment is isolated. That is, the system
   root is never the current folder - instead, the user's Documents
   and Settings folder is, but the permissions on this folder would
   not enable an attacker to place a Trojan horse there. 

Mitigating Factors:
====================
 - An attacker would require the ability to log onto the system
   interactively in order to place the Trojan horse program. It
   could not be placed remotely 

 - As discussed above, dedicated workstations, servers and remote
   terminal server sessions would be at less risk (or, in some cases,
   none at all) from the vulnerability. 

Risk Rating:
============
 - Internet systems: Low
 - Intranet systems: Low
 - Client systems: Moderate

Patch Availability:
===================
 - This vulnerability requires an administrative procedure rather
   than a patch. The needed changes are discussed in the FAQ.  
   Please read the Security Bulletin at
   http://www.microsoft.com/technet/security/bulletin/ms02-064.asp
   for information on obtaining this patch.

Acknowledgment:
===============
 - Jason Miller of Security Focus (http://www.securityfocus.com)

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

THE INFORMATION PROVIDED IN THE MICROSOFT KNOWLEDGE BASE IS PROVIDED
"AS IS" WITHOUT WARRANTY OF ANY KIND. MICROSOFT DISCLAIMS ALL
WARRANTIES, EITHER EXPRESS OR IMPLIED, INCLUDING THE WARRANTIES OF
MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT 
SHALL MICROSOFT CORPORATION OR ITS SUPPLIERS BE LIABLE FOR ANY
DAMAGES WHATSOEVER INCLUDING DIRECT, INDIRECT, INCIDENTAL,
CONSEQUENTIAL, LOSS OF BUSINESS PROFITS OR SPECIAL DAMAGES, EVEN IF
MICROSOFT CORPORATION OR ITS SUPPLIERS HAVE BEEN ADVISED OF THE
POSSIBILITY OF SUCH DAMAGES. SOME STATES DO NOT ALLOW THE EXCLUSION
OR LIMITATION OF LIABILITY FOR CONSEQUENTIAL OR INCIDENTAL DAMAGES
SO THE FOREGOING LIMITATION MAY NOT APPLY.

- -----BEGIN PGP SIGNATURE-----
Version: PGP 7.1

iQEVAwUBPcBlpY0ZSRQxA/UrAQG6NQf/XSZD58pgMpXoZsbu2axijUERbFI3Npq8
YF4gVOf8QTc5/OzZUobaYnTmGjpP2epfL+tNZ/Tj9H2pCD0f/JOE8GNfo03PPI6a
JcA1tbuifpTcf2IQc8NVm/7/Nvh+mSia32Q/LKMyPl/wOqwMHLc0vhlqKGAh+HRa
mfQH9MGBos6JrgZSj7pjvHN4+aD++jfo6Jg/v8jCqLHYL7iarNjwLygnyMfPx8Vs
agEMYDcNG7nk9WnY1vDnQtlWgBFYcgrWxNlnzRf7cadLCYnlrvJBEspROq1EF2Tx
LS4KbcoAUj/Eruf5/c/BMIt/YI536wTqaNWOy77SThcmnps8llmn0w==
=LepM
- -----END PGP SIGNATURE-----

- --------------------------END INCLUDED TEXT--------------------

You have received this e-mail bulletin as a result of your organisation's
registration with AusCERT. The mailing list you are subscribed to is
maintained within your organisation, so if you do not wish to continue
receiving these bulletins you should contact your local IT manager. If
you do not know who that is, please send an email to auscert@auscert.org.au
and we will forward your request to the appropriate person.

This security bulletin is provided as a service to AusCERT's members.  As
AusCERT did not write the document quoted above, AusCERT has had no control
over its content.  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.

NOTE: This is only the original release of the security bulletin.  It may
not be updated when updates to the original are made.  If downloading at
a later date, it is recommended that the bulletin is retrieved directly
from the original authors to ensure that the information is still current.

Contact information for the authors of the original document is included
in the Security Bulletin above.  If you have any questions or need further
information, please contact them directly.

Previous advisories and external security bulletins can be retrieved from:

        http://www.auscert.org.au/Information/advisories.html

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 7031
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 member emergencies only.

-----BEGIN PGP SIGNATURE-----
Version: 2.6.3i
Charset: noconv
Comment: ftp://ftp.auscert.org.au/pub/auscert/AUSCERT_PGP.key

iQCVAwUBPcJumih9+71yA2DNAQGIIAP/dPlpo/U/6g7xKuz6DuI9msun4w7WlK0i
5sBKM9gWmJqsD9Rob8WEpP3pennN5ha7p7JIiHXYJsREsKC7BXmPmemJ3CUbqPRi
Ibz7icF1JuclJUPloiSuefTcgexy5hwiJFT24kBeC/Yx2V64o3SLwO4n3gIaOZ64
oHkmYx1vbW0=
=q0y5
-----END PGP SIGNATURE-----