Protect yourself against future threats.
-----BEGIN PGP SIGNED MESSAGE-----
===========================================================================
AUSCERT External Security Bulletin Redistribution
ESB-2002.279 -- Microsoft Security Bulletin MS02-029
Unchecked Buffer in Remote Access Service Phonebook
Could Lead to Code Execution (Q318138)
13 June 2002
===========================================================================
AusCERT Security Bulletin Summary
---------------------------------
Product: Routing and Remote Access Server (RRAS)
Vendor: Microsoft
Operating System: Windows NT 4.0
Windows NT 4.0 Terminal Server
Windows 2000
Windows XP
Impact: Denial of Service
Execute Arbitrary Code/Commands
Access Required: Existing Account
- --------------------------BEGIN INCLUDED TEXT--------------------
- -----BEGIN PGP SIGNED MESSAGE-----
- - ----------------------------------------------------------------------
Title: Unchecked Buffer in Remote Access Service Phonebook Could
Lead to Code Execution (Q318138)
Date: 12 June 2002
Software: Windows NT 4.0, NT 4.0 Terminal Server Edition, 2000, XP,
Routing and Remote Access Server (RRAS)
Impact: Local Privilege Escalation
Max Risk: Critical
Bulletin: MS02-029
Microsoft encourages customers to review the Security Bulletin at:
http://www.microsoft.com/technet/security/bulletin/MS02-029.asp.
- - ----------------------------------------------------------------------
Issue:
======
The Remote Access Service (RAS) provides dial-up connections between
computers and networks over phone lines. RAS is delivered as a native
system service in Windows NT 4.0, Windows 2000 and Windows XP, and
also is included in a separately downloadable Routing and Remote
Access Server (RRAS) for Windows NT 4.0. All of these implementations
include a RAS phonebook, which is used to store information about
telephone numbers, security, and network settings used to dial-up
remote systems.
A flaw exists in the RAS phonebook implementation: a phonebook value
is not properly checked, and is susceptible to a buffer overrun. The
overrun could be exploited for either of two purposes: causing a
system failure, or running code on the system with LocalSystem
privileges. If an attacker were able to log onto an affected server
and modify a phonebook entry using specially malformed data, then
made a connection using the modified phonebook entry, the specially
malformed data could be run as code by the system.
Mitigating Factors:
====================
- The vulnerability could only be exploited by an attacker who had
the appropriate credentials to log onto an affected system.
- Best practices suggests that unprivileged users not be allowed to
interactively log onto business-critical servers. If this
recommendation has been followed machines such as domain
controllers, ERP servers, print and file servers, database
servers, and others would not be at risk from this vulnerability.
Risk Rating:
============
- Internet systems: Low
- Intranet systems: Critical
- Client systems: Moderate
Patch Availability:
===================
- A patch is available to fix this vulnerability. Please read the
Security Bulletin at
http://www.microsoft.com/technet/security/bulletin/ms02-029.asp
for information on obtaining this patch.
Acknowledgment:
===============
- David Litchfield of Next Generation Security Software Ltd.
(http://www.nextgenss.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
iQEVAwUBPQeZxo0ZSRQxA/UrAQFRlwf/ViegQSKTAFGtyNcKMNu1LQykVOa1sLWw
vsgzuOZWY6HaOtIn6TjMGNEc1OCRCXB776fbUc33FpSW1zpHGxKQkD7rWw6Z3NdK
lhdgCyTSa0kuOm6KysxFMvX3LNBi2IS3Pgz9CteymVgVE0bX1nyglj7z9+D+m/W4
Bu6tAsfmJP0roFbA0s3KfiTXytL8b0nPNgHZbMGRRn/bBnhxCLw/yBE1y667oujQ
/1uPukkAfhTQDV6nFmHMkSmcovIX4jQ3dLv/0oSVA1kJlsMLIBiD2ivQUn8DcMVa
W4sPdM8NbpJCfTuifHWbvipqO1NleEbjS8kTmz4Su6pwRIbh8xSp3g==
=ta2r
- -----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.
-----BEGIN PGP SIGNATURE-----
Version: 2.6.3i
Charset: noconv
Comment: ftp://ftp.auscert.org.au/pub/auscert/AUSCERT_PGP.key
iQCVAwUBPQi6kSh9+71yA2DNAQEYCAP/cL2PC3Eex0AvzRf01OKUhEUPYihdwpZ0
sEBuJ/DinYAe1MbaN2Q1onOD8IxWFN/VofJAOxyair+WD2hfVsGVGZfy/256PIkH
HYDzsRO7dQ0cM/C27LOzdnf9Vr/5C3fjcRo27SaxfHgEGa/uigyx6mGxrChNfkCu
tuBy3SLBcSU=
=/2nt
-----END PGP SIGNATURE-----