Article ID: 329170
Article Last Modified on 12/1/2007
APPLIES TO
- Microsoft Windows XP Professional x64 Edition
- Microsoft Windows XP Home Edition
- Microsoft Windows XP Professional
- Microsoft Windows XP Tablet PC Edition
- Microsoft Windows 2000 Advanced Server
- Microsoft Windows 2000 Professional Edition
- Microsoft Windows 2000 Server
This article was previously published under Q329170
SYMPTOMS
Support for the Server Message Block (SMB) protocol is included in all versions of Windows. Although SMB is a file-sharing protocol, SMB is also used for other purposes. One of these purposes is disseminating Group Policy settings from domain controllers to computers that log on. Beginning with Windows 2000, it is possible to improve the integrity of SMB sessions by digitally signing all packets in a session. Windows 2000 and Windows XP can be configured to always sign, never sign, or sign only if the other party requires it.
A flaw in the implementation of SMB signing in Windows 2000 and Windows XP can permit an attacker to silently downgrade the SMB signing settings on an affected computer. To do this, an attacker must have access to the session negotiation data as it is exchanged between a client and server, and must be able to modify the data in a way that exploits the flaw. This can cause either or both computers to send unsigned data no matter what signing policy the administrator sets. After the attacker downgrades the signing setting, the attacker can continue to monitor and change data in the session. The lack of signing prevents the communicators from detecting the changes.
Although this vulnerability can be exploited to expose any SMB session to tampering, the most serious case involves changing Group Policy settings as they are disseminated from a Windows 2000-based domain controller to a newly logged-on network client. By doing this, an attacker can take actions such as adding users to the local Administrators group or installing and running code on the computer. Note that Windows XP cannot be used as a domain controller. Therefore, this scenario does not apply to Windows XP. This is the highest-risk scenario that is associated with the vulnerability.
RESOLUTION
Windows XP service pack information
To resolve this problem, obtain the latest service pack for Microsoft Windows XP. For additional information, click the following article number to view the article in the Microsoft Knowledge Base:
322389 How to obtain the latest Windows XP service pack
Windows XP hotfix information
Download information
The following files are available for download from the Microsoft Download Center:
32-bit: ![[GRAPHIC: Download]](/wiki/index.php?title=File:Download.gif){kind=small}
Download the 329170 package now
64-bit: Download the 329170 package now
Release Date: December 11, 2002
For additional information about how to download Microsoft Support files, click the following article number to view the article in the Microsoft Knowledge Base:
119591 How to Obtain Microsoft Support Files from Online Services
Microsoft scanned this file for viruses. Microsoft used the most current virus-detection software that was available on the date that the file was posted. The file is stored on security-enhanced servers that help to prevent any unauthorized changes to the file.
Restart requirement
You must restart your computer after you apply this update.
Installation information
This update supports the following Setup switches:
- /? Display the list of installation switches.
- /u Unattended mode.
- /f Force other programs to quit when the computer shuts down.
- /n Do not back up files for removal.
- /o Overwrite OEM files without prompting.
- /z Do not restart when installation is complete.
- /q Quiet mode (no user interaction).
- /l List installed hotfixes.
- /x Extracts the files without running Setup.
For example, the following command line installs the update without any user intervention and then does not force the computer to restart:
q329170_wxp_sp2_x86_enu /q /u /z
Warning Your computer is vulnerable until you restart it.
File information
The English version of this fix has the file attributes (or later) that are listed in the following table. The dates and times for these files are listed in coordinated universal time (UTC). When you view the file information, it is converted to local time. To find the difference between UTC and local time, use the Time Zone tab in the Date and Time tool in Control Panel.
The following files are installed in the %Windir%\System32\Drivers folder.
Windows XP Date Time Version Size File name -------------------------------------------------------------- 31-Oct-2002 19:45 5.1.2600.105 322,304 Srv.sys Windows XP SP1, Windows XP Tablet PC Edition Date Time Version Size File name -------------------------------------------------------------- 20-Dec-2002 17:36 5.1.2600.1154 322,048 Srv.sys Windows XP 64-Bit Edition Date Time Version Size File name -------------------------------------------------------------- 31-Oct-2002 19:45 5.1.2600.105 1,142,016 Srv.sys Windows XP 64-Bit Edition SP1 Date Time Version Size File name -------------------------------------------------------------- 20-Dec-2002 17:36 5.1.2600.1154 1,140,480 Srv.sys
Note If your network is affected, you must install this fix on all Windows XP-based clients in your network.
Windows 2000 service pack information
To resolve this problem, obtain the latest service pack for Microsoft Windows 2000. For additional information, click the following article number to view the article in the Microsoft Knowledge Base:
260910 How to Obtain the Latest Windows 2000 Service Pack
Windows 2000 hotfix information
Download information
The following files are available for download from the Microsoft Download Center:
All Languages except NEC Japanese: Download the 329170 package now
NEC Japanese: Download the 329170 package now
Release Date: December 11, 2002
For additional information about how to download Microsoft Support files, click the following article number to view the article in the Microsoft Knowledge Base:
119591 How to Obtain Microsoft Support Files from Online Services
Microsoft scanned this file for viruses. Microsoft used the most current virus-detection software that was available on the date that the file was posted. The file is stored on security-enhanced servers that help to prevent any unauthorized changes to the file.
Restart requirement
Because of file dependencies, this update requires Windows 2000 Service Pack 2 (SP2) or Service Pack 3 (SP3). For additional information, click the article number below to view the article in the Microsoft Knowledge Base:
260910 How to Obtain the Latest Windows 2000 Service Pack
Installation Information
You must restart your computer after you apply this update. This update supports the following Setup switches:
- /? Display the list of installation switches.
- /u Unattended mode.
- /f Force other programs to quit when the computer shuts down.
- /n Do not back up files for removal.
- /o Overwrite OEM files without prompting.
- /z Do not restart when installation is complete.
- /q Quiet mode (no user interaction).
- /l List installed hotfixes.
- /x Extracts the files without running Setup.
For example, the following command line installs the update without any user intervention and then does not force the computer to restart:
q329170_w2k_sp4_x86_en /q /u /z
Warning Your computer is vulnerable until you restart it.
File Information
The English version of this fix has the file attributes (or later) that are listed in the following table. The dates and times for these files are listed in coordinated universal time (UTC). When you view the file information, it is converted to local time. To find the difference between UTC and local time, use the Time Zone tab in the Date and Time tool in Control Panel.
The following files are installed in the %Windir%\System32\ folder:
Date Time Version Size File name ------------------------------------------------------------ 01-Nov-2002 16:55 5.0.2195.6090 250,640 Localspl.dll 01-Nov-2002 16:55 5.0.2195.6023 381,712 Printui.dll 23-Oct-2002 15:05 5.0.2195.6100 138,752 Sp3res.dll 01-Nov-2002 16:55 5.0.2195.6047 79,632 Spoolss.dll 31-Oct-2002 00:45 5.0.2195.6110 237,456 Srv.sys 01-Nov-2002 16:55 5.0.2195.6110 74,000 Srvsvc.dll 01-Nov-2002 16:55 5.0.2195.6044 84,752 Win32spl.dll 01-Nov-2002 16:55 5.0.2195.6032 114,448 Winspool.drv 01-Nov-2002 16:55 5.0.2195.6103 55,056 Wlnotify.dll
STATUS
Microsoft has confirmed that this problem may cause a degree of security vulnerability in the Microsoft products that are listed in the "Applies to" section.
Windows XP
This problem was first corrected in Microsoft Windows XP Service Pack 2.
Windows 2000
This problem was first corrected in Microsoft Windows 2000 Service Pack 4.
MORE INFORMATION
For more information about this vulnerability, visit the following Microsoft Web site:
Additional query words: security_patch
Keywords: kbhotfixserver kbqfe atdownload kbwinxpsp2fix kbenv kbsecurity kbwin2ksp4fix kbbug kbfix kbwin2000presp4fix kbwinxppresp2fix KB329170
