__________________________________________________________ The U.S. Department of Energy Computer Incident Advisory Capability ___ __ __ _ ___ / | /_\ / \___ __|__ / \ \___ __________________________________________________________ INFORMATION BULLETIN Flaw in Microsoft Windows Message Handling through Utility Manager Could Enable Privilege Elevation [Microsoft Security Bulletin MS03-025] July 10, 2003 17:00 GMT Number N-116 ______________________________________________________________________________ PROBLEM: A security vulnerability exists in the way that Utility Manager handles Windows messages because the control that provides the list of accessibility options to the user does not properly validate Windows messages sent to it. It's possible for one process in the interactive desktop to use a specific Windows message to cause the Utility Manager process to execute a callback function at the address of its choice. Because the Utility Manager process runs at higher privileges than the first process, this would provide the first process with a way of exercising those higher privileges. SOFTWARE: Microsoft Windows 2000 DAMAGE: An attacker who had the ability to log on to a system interactively could potentially run a program that could send a specially crafted Windows message upon the Utility Manager process, causing it to take any action the attacker specified. This would give the attacker complete control over the system. SOLUTION: Apply patch as stated in Microsoft's security bulletin. ______________________________________________________________________________ VULNERABILITY The risk is MEDIUM. The attack cannot be exploited remotely, ASSESSMENT: and the attacker would have to have the ability to interactively log on to the system. ______________________________________________________________________________ LINKS: CIAC BULLETIN: http://www.ciac.org/ciac/bulletins/n-116.shtml ORIGINAL BULLETIN: http://www.microsoft.com/technet/treeview/ default.asp?url=/technet/security/bulletin/MS03-025.asp PATCHES: http://microsoft.com/downloads/ details.aspx?FamilyId=D415A4AC-E13A-4E8A-BE25-85E7DF686F61 &displaylang=en ______________________________________________________________________________ [***** Start Microsoft Security Bulletin MS03-025 *****] Microsoft Security Bulletin MS03-025 Flaw in Windows Message Handling through Utility Manager Could Enable Privilege Elevation (822679) Originally posted: July 9, 2003 Summary Who should read this bulletin: Customers using Microsoft® Windows® 2000 Impact of vulnerability: Privilege elevation Maximum Severity Rating: Important Recommendation: Customers should install the patch at the earliest opportunity. End User Bulletin: An end user version of this bulletin is available at: http://www.microsoft.com/security/security_bulletins/ms03-025.asp. Affected Software: * Microsoft Windows 2000 Not Affected Software: * Microsoft Windows Me * Microsoft Windows NT Server 4.0 * Microsoft Windows NT Server, Terminal Services Edition * Microsoft Windows XP * Microsoft Windows Server 2003 Technical details Technical description: Microsoft Windows 2000 contains support for Accessibility options within the operating system. Accessibility support is a series of assistive technologies within Windows that allow users with disabilities to still be able to access the functions of the operating system. Accessibility support is enabled or disabled through shortcuts built into the operating system, or through the Accessibility Utility Manager. Utility Manager is an accessibility utility that allows users to check the status of accessibility programs (Microsoft Magnifier, Narrator, On–Screen Keyboard) and to start or stop them. There is a flaw in the way that Utility Manager handles Windows messages. Windows messages provide a way for interactive processes to react to user events (for example, keystrokes or mouse movements) and communicate with other interactive processes. A security vulnerability results because the control that provides the list of accessibility options to the user does not properly validate Windows messages sent to it. It's possible for one process in the interactive desktop to use a specific Windows message to cause the Utility Manager process to execute a callback function at the address of its choice. Because the Utility Manager process runs at higher privileges than the first process, this would provide the first process with a way of exercising those higher privileges. By default, the Utility Manager contains controls that run in the interactive desktop with Local System privileges. As a result, an attacker who had the ability to log on to a system interactively could potentially run a program that could send a specially crafted Windows message upon the Utility Manager process, causing it to take any action the attacker specified. This would give the attacker complete control over the system. The attack cannot be exploited remotely, and the attacker would have to have the ability to interactively log on to the system. 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 on to such systems interactively; without such privileges, an attacker could not exploit the vulnerability. Severity Rating: Windows 2000 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-2003-0350 Tested Versions: Microsoft tested Windows Me, Windows NT Server 4.0, Windows NT Server, Terminal Server Edition, Windows 2000, Windows XP, and Windows Server 2003 to assess whether they are affected by these vulnerabilities. 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 2000: http://microsoft.com/downloads/ details.aspx?FamilyId=D415A4AC-E13A-4E8A-BE25-85E7DF686F61&displaylang=en Additional information about this patch Installation platforms: The Windows 2000 patch can be installed on systems running Windows 2000 Service Pack 3. In addition, the fix for this issue is included in Windows 2000 Service Pack 4. Inclusion in future service packs: The fix for this issue is included in Windows 2000 Service Pack 4. Reboot needed: Yes Patch can be uninstalled: Yes Superseded patches: None. Verifying patch installation: * 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\Q822679 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\Q822679\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 Chris Paget of Next Generation Security Software Ltd. for reporting this issue to us and working with us to protect customers. Support: * Microsoft Knowledge Base article 822679 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 9, 2003): Bulletin Created. [***** End Microsoft Security Bulletin MS03-025 *****] _______________________________________________________________________________ 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 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. 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