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Revised: Microsoft Security Bulletin MS02-071: Flaw in Windows WM_TIMER Message Handling Could Enable Privilege Elevation (328310)
From: "Microsoft" <0_47374_04BF067D-4CF8-4245-B5C1-58573E5746A8_US () Newsletters Microsoft com>
Date: Wed, 30 Apr 2003 21:35:51 -0700
-----BEGIN PGP SIGNED MESSAGE----- - ---------------------------------------------------------------------- Title: Flaw in Windows WM_TIMER Message Handling Could Enable Privilege Elevation (328310) Released: December 11, 2002 Revised: April 30, 2003 (version 3.0) Software: Microsoft(r) Windows(r) NT 4.0, Windows 2000, and Windows XP Impact: Privilege elevation Max Risk: Important Bulletin: MS02-071 Microsoft encourages customers to review the Security Bulletin at: http://www.microsoft.com/technet/security/bulletin/MS02-071.asp http://www.microsoft.com/security/security_bulletins/ms02-071.asp - ---------------------------------------------------------------------- Reason for Revision: ==================== Subsequent to the release of this patch Microsoft identified a problem affected Windows NT 4.0 TSE multi processor systems which was causing them to fail. The patch should have been installable on both single and multi processor system and the installer should have copied the correct binaries onto the system depending on whether the system was single or multi processor. However an installer error meant that the correct binaries were not being copied onto multi processor systems, causing them to fail under certain scenarios. Microsoft has updated the patch for Windows NT 4.0 TSE to correct this error. It should be noted that this patch only corrects an installer problem with multi processor Windows NT 4.0 TSE systems - there is no requirement to re-install the patch on single processor systems as the installer functions correctly on those systems. Issue: ====== Subsequent to the release of this bulletin it was determined that the patch for Microsoft Windows NT 4.0 machines introduced an error that could, under certain configurations, cause NT 4.0 to fail. Microsoft has investigated this issue and has released an updated patch for Windows NT 4.0. The bulletin has been updated to include the new download links for the NT 4.0 patch. The error did not affect NT 4.0 TSE, except for the Japanese Language. Customers running the Japanese version of NT 4.0 TSE should apply the updated fix. Customers who have installed the patch on Microsoft Windows 2000 and Windows XP are unaffected by this error. Windows messages provide a way for interactive processes to react to user events (e.g., keystrokes or mouse movements) and communicate with other interactive processes. One such message, WM_TIMER, is sent at the expiration of a timer, and can be used to cause a process to execute a timer callback function. A security vulnerability results because it's possible for one process in the interactive desktop to use a WM_TIMER message to cause another process to execute a callback function at the address of its choice, even if the second process did not set a timer. If that second process had higher privileges than the first, this would provide the first process with a way of exercising them. By default, several of the processes running in the interactive desktop do so with LocalSystem privileges. As a result, an attacker who had the ability to log onto a system interactively could potentially run a program that would levy a WM_TIMER request upon such a process, causing it to take any action the attacker specified. This would give the attacker complete control over the system. In addition to addressing this vulnerability, the patch also makes changes to several processes that run on the interactive desktop with high privileges. Although none of these would, in the absence of the TM_TIMER vulnerability, enable an attacker to gain privileges on the system, we have included them in the patch to make the services more robust. Mitigating Factors: ==================== - -An attacker would need valid logon credentials to exploit the vulnerability. It could not be exploited remotely. - -Properly secured servers would be at little risk from this vulnerability. Standard best practices recommend only allowing trusted administrators to log onto such systems interactively; without such privileges, an attacker could not exploit the vulnerability. Risk Rating: ============ Important Patch Availability: =================== - A patch is available to fix this vulnerability. Please read the Security Bulletins at http://www.microsoft.com/technet/security/bulletin/ms02-071.asp http://www.microsoft.com/security/security_bulletins/ms02-071.asp for information on obtaining this patch. - ----------------------------------------------------------------- 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 iQEVAwUBPrAKMY0ZSRQxA/UrAQGuiAgAhKJcRoS/2A4h9/muCDQZbWmwsbxOoQLI BjXm2WU8xhsWhpo3uF/HAqofwyuosH6NQMDT5loM+ZQu4efCO1n06Z4olUFPKOe5 Idyx6o+rqEKqq9Sz5VdSFbqv3O+DJRTwJN6p7jKboH7ufRvuWhoVkiMub5NUzq80 mdPsvjSdu+V4j4WUGDH+RtZbYp8Jfx7qCypJYkvo/G8Tk6RxbVVeee4pH/sV0O5c zYmE2hT3BS4fEDJdEF/q68rU34oxKQQCu907pym9ZSK6XjFuIvtpR5qy9uATLZbR jv58DymcDPiHYAhgkHtwSZBde47X1uVEC+wh6rwBGP3r87A7Pfl6sw== =t1cO -----END PGP SIGNATURE----- ******************************************************************* You have received this e-mail bulletin because of your subscription to the Microsoft Product Security Notification Service. For more information on this service, please visit http://www.microsoft.com/technet/security/notify.asp. 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- Revised: Microsoft Security Bulletin MS02-071: Flaw in Windows WM_TIMER Message Handling Could Enable Privilege Elevation (328310) Microsoft (Apr 30)