TUCoPS :: Windows :: n-115.txt

TUCoPS :: Windows :: n-115.txt
Buffer Overrun in Microsoft Windows Could Lead to Data Corruption (CIAC N-115)

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The U.S. Department of Energy
Computer Incident Advisory Capability
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INFORMATION BULLETIN

Buffer Overrun in Microsoft Windows Could Lead to Data Corruption
[Microsoft Security Bulletin MS03-024]

July 10, 2003 17:00 GMT Number N-115
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PROBLEM: A flaw exists in the way that the server validates the
parameters of an SMB (Server Message Block) packet. The server
is not properly validating the buffer length established by the
packet. If the client specifies a buffer length that is less
than what is needed, it can cause the buffer to overrun.
SOFTWARE: * Microsoft Windows NT Server 4.0
* Microsoft Windows NT Server 4.0, Terminal Server Edition
* Microsoft Windows 2000
* Windows XP Professional
DAMAGE: By sending a specially crafted SMB packet request, an attacker
could cause a buffer overrun to occur. If exploited, this could
lead to data corruption, system failure, or in the worst case,
allow an attacker to run code of their choice.
SOLUTION: Apply patches as stated in Microsoft's security bulletin.
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VULNERABILITY The risk is MEDIUM. In order to exploit this vulnerability, an
ASSESSMENT: attacker would need a valid user account, and be authenticated
by the server prior to sending an SMB packet to it.
______________________________________________________________________________
LINKS:
CIAC BULLETIN: http://www.ciac.org/ciac/bulletins/n-115.shtml
ORIGINAL BULLETIN:
http://www.microsoft.com/technet/treeview/
default.asp?url=/technet/security/bulletin/MS03-024.asp
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[***** Start Microsoft Security Bulletin MS03-024 *****]

Microsoft Security Bulletin MS03-024

Buffer Overrun in Windows Could Lead to Data Corruption (817606)
Originally posted: July 09, 2003

Summary
Who should read this bulletin: Customers using Microsoft® Windows® NT,
Microsoft Windows 2000, or Microsoft Windows XP

Impact of vulnerability: Allow an attacker to execute code of their
choice

Maximum Severity Rating: Important

Recommendation: Administrators should consider installing the patch.

Affected Software:

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

Not Affected Software:

* Microsoft Windows Server 2003

Technical details

Technical description:

Server Message Block (SMB) is the Internet Standard protocol that Windows
uses to share files, printers, serial ports, and to communicate between
computers using named pipes and mail slots. In a networked environment,
servers make file systems and resources available to clients. Clients
make SMB requests for resources, and servers make SMB responses in what’s
described as a client server request-response protocol.

A flaw exists in the way that the server validates the parameters of an
SMB packet. When a client system sends an SMB packet to the server system,
it includes specific parameters that provide the server with a set of
“instructions.” In this case, the server is not properly validating the
buffer length established by the packet. If the client specifies a buffer
length that is less than what is needed, it can cause the buffer to be
overrun.

By sending a specially crafted SMB packet request, an attacker could cause
a buffer overrun to occur. If exploited, this could lead to data corruption,
system failure, or—in the worst case—it could allow an attacker to run the
code of their choice. An attacker would need a valid user account and would
need to be authenticated by the server to exploit this flaw.

Mitigating factors:

* Windows Server 2003 is not affected by this vulnerability.
* By default, it is not possible to exploit this flaw anonymously. The
attacker would have to be authenticated by the server prior to attempting
to send a SMB packet to it.
* Blocking port 139/445 at the firewall will prevent the possibility of an
attack from the Internet.

Severity Rating: Windows NT Server 4.0 Important
Windows NT Server 4.0,
Terminal Server Edition Important
Windows 2000 Important
Windows XP Professional 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-2003-0345

Tested Versions:
Microsoft tested Windows NT Server 4.0, Windows NT Server 4.0, Terminal
Services Edition, 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

* Windows NT 4.0 Server

* Windows NT 4.0, Terminal Server Edition

* Windows 2000 Server

* Windows XP 32 bit Edition

* Windows XP 64 bit Edition

Additional information about this patch

Installation platforms:
This patch can be installed on systems running:

* Windows NT Server 4.0:
The Windows NT Server 4.0 patch can be installed on systems running
Windows NT Server 4.0 Service Pack 6a.

* Windows NT Server, Terminal Server Edition:
The Windows NT Server, Terminal Server Edition patch can be installed on
systems running Windows NT Server, Terminal Server Edition Service Pack 6.

* Windows 2000:
The Windows 2000 patch can be installed on systems running Windows 2000
Service Pack 3.

* Windows XP:
The patch for Windows XP can be installed on systems running Windows XP
Gold or Windows XP Service Pack 1.

Inclusion in future service packs:

* The fix for this issue is included in Service Pack 4.
* The fix for this issue will be included in 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
817606 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 817606 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\Q817606.

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\Q817606\Filelist.

* Windows XP:

* If installed on Windows XP Gold:
To verify that the patch has been installed, confirm that the following
registry key has been created on the machine:
HKLM\Software\Microsoft\Updates\Windows XP\SP1\Q817606.

To verify the individual files, use the date/time and version information
provided in the following registry key:
HKLM\Software\Microsoft\Updates\Windows XP\SP1\Q817606\Filelist.

* If installed on Windows XP Service Pack 1:
To verify that the patch has been installed, confirm that the following
registry key has been created on the machine:
HKLM\Software\Microsoft\Updates\Windows XP\SP2\Q817606.

To verify the individual files, use the date/time and version information
provided in the following registry key:
HKLM\Software\Microsoft\Updates\Windows XP\SP2\Q817606\Filelist.

Caveats:
None

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:

Acknowledgments

Microsoft thanks Jeremy Allison and Andrew Tridgell, Samba Team for reporting
this issue to us and working with us to protect customers.

Support:

* Microsoft Knowledge Base article 817606 discusses this issue and will be available
approximately 24 hours after the release of this bulletin. 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 July 09, 2003: Bulletin Created.

[***** End Microsoft Security Bulletin MS03-024 *****]

_______________________________________________________________________________

CIAC wishes to acknowledge the contributions of Microsoft Corporation 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
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