Date: 13 November 2009
References: ESB-2010.0341
Click here for printable version
Click here for PGP verifiable version
-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1
===========================================================================
AUSCERT External Security Bulletin Redistribution
ESB-2009.1527
Vulnerability in SMB Could Allow Denial of Service
14 November 2009
===========================================================================
AusCERT Security Bulletin Summary
---------------------------------
Product: SMB
Publisher: Microsoft
Operating System: Windows 7
Windows Server 2008
Impact/Access: Denial of Service -- Remote with User Interaction
Resolution: Mitigation
CVE Names: CVE-2009-3676
Reference: http://www.auscert.org.au/11954
Original Bulletin:
http://www.microsoft.com/technet/security/advisory/977544.mspx
Comment: Please note it is Server 2008 R2 that is affected, along with
Windows 7.
Exploit code for this vulnerability has been made public.
- --------------------------BEGIN INCLUDED TEXT--------------------
Microsoft Security Advisory (977544)
Vulnerability in SMB Could Allow Denial of Service
Published: November 13, 2009
Version: 1.0
General Information
Executive Summary
Microsoft is investigating new public reports of a possible denial of
service vulnerability in the Server Message Block (SMB) protocol. This
vulnerability cannot be used to take control of or install malicious
software on a users system. However, Microsoft is aware that detailed
exploit code has been published for the vulnerability. Microsoft is not
currently aware of active attacks that use this exploit code or of
customer impact at this time. Microsoft is actively monitoring this
situation to keep customers informed and to provide customer guidance as
necessary.
Affected Software
Windows 7 for 32-bit Systems
Windows 7 for x64-based Systems
Windows Server 2008 R2 for x64-based Systems*
Windows Server 2008 R2 for Itanium-based Systems
*Server Core installation affected.
Workarounds
Block TCP ports 139 and 445 at the firewall
These ports are used to initiate a connection with the affected component.
Blocking TCP ports 139 and 445 at the firewall will help protect systems
that are behind that firewall from attempts to exploit this vulnerability.
Microsoft recommends that you block all SMB communications to and from the
Internet to help prevent attacks. For more information about ports, see
TCP and UDP Port Assignments.
Impact of Workaround: Several Windows services use the affected ports.
Blocking connectivity to the ports may cause various applications or
services to not function. Some of the applications or services that could
be impacted are listed below:
Applications that use SMB (CIFS)
Applications that use mailslots or named pipes (RPC over SMB)
Server (File and Print Sharing)
Group Policy
Net Logon
Distributed File System (DFS)
Terminal Server Licensing
Print Spooler
Computer Browser
Remote Procedure Call Locator
Fax Service
Indexing Service
Performance Logs and Alerts
Systems Management Server
License Logging Service
How to undo the workaround. Unblock TCP ports 139 and 445 at the firewall.
- --------------------------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.
NOTE: Third Party Rights
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 follow or act on information or advice
contained in this security bulletin is the responsibility of each user or
organisation, and should be considered in accordance with your organisation's
site policies and procedures. AusCERT takes no responsibility for consequences
which may arise from following or acting on information or advice contained in
this security bulletin.
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 author's website 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/render.html?cid=1980
If you believe that your computer system has been compromised or attacked in
any way, we encourage you to let us know by completing the secure National IT
Incident Reporting Form at:
http://www.auscert.org.au/render.html?it=3192
===========================================================================
Australian Computer Emergency Response Team
The University of Queensland
Brisbane
Qld 4072
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-----
Comment: http://www.auscert.org.au/render.html?it=1967
iD8DBQFK/hTANVH5XJJInbgRAha3AJ41OY7iNEZTWm84xAZNB8Swsm0FtACeKurY
Taw5pdauGuW/FgqFkTGpw68=
=gUpV
-----END PGP SIGNATURE-----
|