TUCoPS :: Windows :: n-054.txt

TUCoPS :: Windows :: n-054.txt
Microsoft Unchecked Buffer in Windows Component (CIAC N-054)

__________________________________________________________

The U.S. Department of Energy
Computer Incident Advisory Capability
___ __ __ _ ___
/ | /_\ /
\___ __|__ / \ \___
__________________________________________________________

INFORMATION BULLETIN

Microsoft Unchecked Buffer in Windows Component Could Cause
Web Server Compromise
[Microsoft Security Bulletin MS03-007]

March 17, 2003 16:00 GMT Number N-054
[Revised 23 April 2003]
[Revised 28 May 2003]
______________________________________________________________________________
PROBLEM: A vulnerability has been identified in the World Wide Web
Distributed Authoring and Versioning (WebDAV) protocol. WebDAV
uses IIS to pass requests to and from Windows 2000. When IIS
receives a WebDAV request, it typically processes the request
and then acts on it. However, if the request is formed in a
particular way, a buffer overrun can result because of a flaw
in one of the components called by WebDAV which does not
correctly check parameters.
PLATFORM: Microsoft Windows 2000 running IIS 5.0
DAMAGE: By exploiting the buffer overrun, a remote attacker could gain
administrator access to the system.
SOLUTION: Apply available patch.
______________________________________________________________________________
VULNERABILITY The risk is HIGH. IIS 5.0 is installed by default on all server
ASSESSMENT: versions of Windows 2000. It has been reported that an exploit
for this attack exists.
______________________________________________________________________________
LINKS:
CIAC BULLETIN: http://www.ciac.org/ciac/bulletins/n-054.shtml
ORIGINAL BULLETIN:
http://www.microsoft.com/technet/treeview/default.asp?
url=/technet/security/bulletin/MS03-007.asp
PATCHES: http://microsoft.com/downloads/details.aspx?FamilyId=
C9A38D45-5145-4844-B62E-C69D32AC929B&displaylang=en
____________________________________________________________________________

[***** Start Microsoft Security Bulletin MS03-007 *****]

Microsoft Security Bulletin MS03-007

Unchecked Buffer In Windows Component Could Cause
Server Compromise (815021)
Originally posted: March 17, 2003

Updated: May 28, 2003

Summary
Who should read this bulletin: Systems administrators running Microsoft ®
Windows ® NT 4.0, Windows 2000, and Windows XP.

Impact of vulnerability: Run code of attacker’s choice

Maximum Severity Rating: Critical

Recommendation: Systems administrators should apply the patch immediately

End User Bulletin: An end user version of this bulletin is available at:
http://www.microsoft.com/security/security_bulletins/ms03-007.asp

Affected Software:

* Microsoft Windows NT 4.0
* Microsoft Windows NT 4.0 Terminal Server Edition
* Microsoft Windows 2000
* Microsoft Windows XP

Not Affected Software:

* Microsoft Windows Server 2003

Technical details
Technical description:

Microsoft originally released this security bulletin on March 17, 2003. At
that time, Microsoft was aware of a publicly available exploit that was being
used to attack Windows 2000 Servers running IIS 5.0. The attack vector in this
case was WebDAV although the underlying vulnerability was in a core operating
system component, ntdll.dll. Microsoft issued a patch to protect Windows 2000
customers shortly afterwards, but also continued to investigate the underlying
vulnerability. During the course of that investigation, Microsoft found that
Windows NT 4.0 also contains the underlying vulnerability in ntdll.dll, however
it does not support WebDAV and therefore the known exploit was not effective
against Windows NT 4.0. In addition, Microsoft has recently been made aware of
this vulnerability as well in Windows XP. However, like Windows NT 4.0, Windows
XP does not install Internet Information Services (IIS) by default. Microsoft
has now released patches for Windows NT 4.0 and Windows XP.

Microsoft Windows 2000 supports the World Wide Web Distributed Authoring and
Versioning (WebDAV) protocol. WebDAV, defined in RFC 2518, is a set of
extensions to the Hyper Text Transfer Protocol (HTTP) that provide a standard for
editing and file management between computers on the Internet. A security
vulnerability is present in a Windows component used by WebDAV and results because
a core operating system component, ntdll.dll, contains an unchecked buffer.

An attacker could exploit the vulnerability by sending a specially formed HTTP
request to a machine running Internet Information Server (IIS). The request could
cause the server to fail or to execute code of the attacker’s choice. The code
would run in the security context of the IIS service (which, by default, runs in
the LocalSystem context).

Although Microsoft has supplied a patch for this vulnerability and recommends all
affected customers install the patch immediately, additional tools and preventive
measures have been provided that customers can use to block the exploitation of
this vulnerability while they are assessing the impact and compatibility of the
patch. These temporary workarounds and tools are discussed in the “Workarounds”
section in the FAQ below.

Mitigating factors:

* URLScan, which is a part of the IIS Lockdown Tool will block this attack in its
default configuration
* The vulnerability can only be exploited remotely if an attacker can establish a
web session with an affected server
* Windows NT 4.0 and Windows XP do not install Internet Information Services by
default.
* Windows NT 4.0 does not support WebDAV

Severity Rating: Windows NT 4.0 Important
Windows NT 4.0 Terminal Server Edition Important
Windows 2000 Critical
Windows XP Important

The above assessment is based on the types of systems affected by the vulnerability,
their typical deployment patterns, and the effect that exploiting the vulnerability
would have on them.

Vulnerability identifier: CAN-2003-0109

Tested Versions:
Microsoft tested Windows NT 4.0, Windows 2000, Windows XP and Windows Server 2003,
to assess whether they are affected by this vulnerability. Previous versions are no
longer supported, and may or may not be affected by these vulnerabilities.

Patch availability

Download locations for this patch

* Microsoft Windows NT 4.0:

* All except NEC and Chinese - Hong Kong
* Japanese NEC
* Chinese - Hong Kong

* Windows NT 4.0, Terminal Server Edition:

* All

* Microsoft Windows 2000:

* All except Japanese NEC

* Japanese NEC

* Microsoft Windows XP:

* 32-bit Edition
* 64-bit Edition

Additional information about this patch

Installation platforms:
Windows NT 4.0:

This patch can be installed on systems running Windows NT 4.0 Service Pack 6a.

Windows 2000:

This patch can be installed on systems running Windows 2000 Service Pack 2 or
Service Pack 3.

Windows XP:

This patch can be installed on systems running Windows XP Gold or Service Pack 1.

Inclusion in future service packs:
The fix for this issue will be included in Windows 2000 Service Pack 4 and Windows
XP Service pack 2.

Reboot needed: Yes

Patch can be uninstalled: Yes

Superseded patches: None.

Verifying patch installation:

* Windows NT 4.0:
To verify that the patch has been installed on the machine, confirm that all files
listed in the file manifest in Knowledge Base article 815021 are present on the system.

* Windows NT 4.0 Terminal Server Edition:
To verify that the patch has been installed on the machine, confirm that all files
listed in the file manifest in Knowledge Base article 815021 are present on the system.

* Windows 2000:
To verify that the patch has been installed on the machine, confirm that the following
registry key has been created on the machine:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Updates\Windows 2000\SP4\Q815021.

To verify the individual files, use the date/time and version information provided in
the following registry key:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Updates\Windows 2000\SP4\Q815021\Filelist.

* Windows XP:
To verify that the patch has been installed on the machine, confirm that the following
registry key has been created on the machine:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Updates\Windows XP\SP1\Q815021.

To verify the individual files, use the date/time and version information provided in
the following registry key:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Updates\Windows XP\SP1\Q815021\Filelist.

Caveats:

If you are running Windows 2000 SP2, before installing this patch please check the
version of ntoskrnl.exe on your system. To verify the version of ntoskrnl.exe on your
system, perform the following steps:

1. Browse to the %windir%\system32 directory

2. Right-click ntoskrnl.exe

3. Choose properties.

The version information is located on the ‘version’ tab.

Versions of ntoskrnl.exe between 5.0.2195.4797 and 5.0.2195.4928 (inclusive) are not
compatible with this patch. These versions were only distributed with Product Support
Services hotfixes.

If the patch for this issue is installed on a system with one of these versions of
ntoskrnl.exe, the machine will fail on the first reboot with a Stop 0x00000071 message
and will have to be recovered using the Windows 2000 recovery console and the backup
copy of ntdll.dll stored in the “\winnt\$NTUninstallQ815021$” directory.

To update a system with a version of ntoskrnl.exe distributed from Product Support
Services, you must first contact PSS before applying this patch. Information on
contacting Product Support Services can be found at:

http://support.microsoft.com

Alternatively you can upgrade to Windows 2000 SP3 prior to installing this patch or
apply the Windows 2000 patch from MS03-013, which superceeds this patch and corrects
the problem described above.

Localization:
Localized versions of this patch are available at the locations discussed in “Patch
Availability”.

Obtaining other security patches:
Patches for other security issues are available from the following locations:

* Security patches are available from the Microsoft Download Center, and can be most
easily found by doing a keyword search for "security_patch".
* Patches for consumer platforms are available from the WindowsUpdate web site

Other information:

Support:

* Microsoft Knowledge Base article 815021 discusses this issue. Additional Knowledge
Base articles can be found on the Microsoft Online Support web site.
* Technical support is available from Microsoft Product Support Services. There is no
charge for support calls associated with security patches.

Security Resources: The Microsoft TechNet Security Web Site provides additional
information about security in Microsoft products.

Disclaimer:
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.

Revisions:

* V1.0 (March 17, 2003): Bulletin Created.
* V1.1 (March 18, 2003): Added new information in the Caveats under in the Additional
Information section, clarified affected Windows component throughout the bulletin,
added a question regarding IIS 5.0 to the Frequently Asked Questions section, added
a question regarding changes to the Caveats in the Additional Information section to
the Frequently Asked Questions section.
* V2.0 (April 23, 2003): Updated to include details of NT 4.0 patch.
* V2.1 (April 24, 2003): Updated to include download link for NT4 package for Japanese NEC
* V2.2 (April 24, 2003): Provided additional clarification in FAQ regarding supercedence
of Windows 2000 patch by the patch in MS03-013.
* V3.0 (May 28, 2003): Updated to include details of Windows XP patch.
* V3.1 (May 28, 2003): Updated to include correct Windows NT 4.0 and Windows XP
verification keys.
* V3.2 (May 28, 2003): Updated frequently asked questions section regarding IIS 5.1

[***** End Microsoft Security Bulletin MS03-007 *****]

_______________________________________________________________________________

CIAC wishes to acknowledge the contributions of Microsoft for the
information contained in this bulletin.
_______________________________________________________________________________

CIAC, the Computer Incident Advisory Capability, is the computer
security incident response team for the U.S. Department of Energy
(DOE) and the emergency backup response team for the National
Institutes of Health (NIH). CIAC is located at the Lawrence Livermore
National Laboratory in Livermore, California. CIAC is also a founding
member of FIRST, the Forum of Incident Response and Security Teams, a
global organization established to foster cooperation and coordination
among computer security teams worldwide.

CIAC services are available to DOE, DOE contractors, and the NIH. CIAC
can be contacted at:
Voice: +1 925-422-8193 (7x24)
FAX: +1 925-423-8002
STU-III: +1 925-423-2604
E-mail: ciac@ciac.org

Previous CIAC notices, anti-virus software, and other information are
available from the CIAC Computer Security Archive.

World Wide Web: http://www.ciac.org/
Anonymous FTP: ftp.ciac.org

PLEASE NOTE: Many users outside of the DOE, ESnet, and NIH computing
communities receive CIAC bulletins. If you are not part of these
communities, please contact your agency's response team to report
incidents. Your agency's team will coordinate with CIAC. The Forum of
Incident Response and Security Teams (FIRST) is a world-wide
organization. A list of FIRST member organizations and their
constituencies can be obtained via WWW at http://www.first.org/.

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.

LAST 10 CIAC BULLETINS ISSUED (Previous bulletins available from CIAC)

N-044: Red Hat Updated kernel-utils Packages Fix setuid Vulnerability
N-045: Red Hat Updated PAM packages fix bug in pam_xauth Module
N-046: Multiple Vulnerabilities in Oracle Servers
N-047: Microsoft Windows ME Help and Support Center Vulnerability
N-048: SendMail MTA Vulnerability
N-049: Snort RPC Preprocessing Vulnerability
N-050: Sun sendmail(1M) ".forward" Constructs Vulnerability
N-051: Red Hat Updated OpenSSL Packages Fix Timing Attack
N-052: PeopleSoft PeopleTools Remote Command Execution Vulnerability
N-053: Increased Activity Targeting Microsoft Windows Shares