__________________________________________________________ The U.S. Department of Energy Computer Incident Advisory Capability ___ __ __ _ ___ / | /_\ / \___ __|__ / \ \___ __________________________________________________________ INFORMATION BULLETIN Microsoft Authentication Flaw in Windows Debugger [Microsoft Security Bulletin MS02-024] May 24, 2002 18:00 GMT Number M-083 ______________________________________________________________________________ PROBLEM: A flaw exists in the authentication mechanism for the debugging facility. The vulnerability may allow an attacker to cause a running program to run a program of their choice. PLATFORM: Windows NT 4.0, Windows NT 4.0 Server, Terminal Server Edition, Windows 2000 DAMAGE: Exploitation of this vulnerability allows an attacker to run code as the operating system itself, which may allow escalation to administrative privileges. SOLUTION: Apply appropriate patches as prescribed by Microsoft's security bulletin. ______________________________________________________________________________ VULNERABILITY The risk is MEDIUM. This is a privilege elevation ASSESSMENT: vulnerability. A malicious user must have the ability to interactively log on to a system. ______________________________________________________________________________ LINKS: CIAC BULLETIN: http://www.ciac.org/ciac/bulletins/m-083.shtml ORIGINAL BULLETIN: http://www.microsoft.com/technet/treeview/ default.asp?url=/technet/security/bulletin/ MS02-024.asp ______________________________________________________________________________ [***** Start Microsoft Security Bulletin MS02-024 *****] Microsoft Security Bulletin MS02-024 Authentication Flaw in Windows Debugger can Lead to Elevated Privileges (Q320206) Originally posted: May 22, 2002 Summary Who should read this bulletin: Administrators of Microsoft® Windows NT® 4.0, Windows® 2000 systems. Impact of vulnerability: Elevation of Privilege Maximum Severity Rating: Critical Recommendation: System Administrators should apply the patch to all systems that allow unprivileged users to log onto them interactively. Affected Software: * Microsoft Windows NT 4.0 * Microsoft Windows NT 4.0 Server, Terminal Server Edition * Microsoft Windows 2000 Technical details Technical description: The Windows debugging facility provides a means for programs to perform diagnostic and analytic functions on applications as they are running on the operating system. One of these capabilities allows for a program, usually a debugger, to connect to any running program, and to take control of it. The program can then issue commands to the controlled program, including the ability to start other programs. These commands would then execute in the same security context as the controlled program. There is a flaw in the authentication mechanism for the debugging facility such that an unauthorized program can gain access to the debugger. A vulnerability results because an attacker can use this to cause a running program to run a program of her choice. Because many programs run as the operating system, this means that an attacker can exploit this vulnerability to run code as the operating system itself. She could take any action on the system including deleting data, adding accounts with administrative access, or reconfiguring the system. A successful attack requires the ability to logon interactively to the system, either at the console or through a terminal session. Also, an a successful attack requires the introduction of code to exploit this vulnerability. Because best practices recommends restricting the ability to logon interactively on servers, this issue most directly affects client systems and terminal servers. Mitigating factors: * A successful attack requires the ability to logon interactively to the target machine, either directly at the console or through a terminal session. Best practices strongly militate against ever allowing an unprivileged user to interactively log onto business-critical systems such as ERP servers, database servers, domain controllers and the like. If these recommendations have been followed, the vulnerability would principally pose a threat only to systems like workstations and terminal servers. * A successful attack requires that the attacker be able to load code of her choice on the system. Restrictions on a user's ability to load and execute arbitrary code could potentially prevent a successful attack. Severity Rating: Internet Servers Intranet Servers Client Systems ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Windows NT 4.0 Low Moderate Critical Windows 2000 Low Moderate Critical ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 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. The vulnerability requires interactive logons, which are normally heavily restricted on Internet facing systems and moderately restricted on Intranet systems. In addition, the attack requires the introduction of malicious code to the system. Vulnerability identifier: CAN-2002-0367 Tested Versions: Microsoft tested Windows NT 4.0, Windows 2000, and Windows XP 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 * Windows NT 4.0: http://www.microsoft.com/ntserver/nts/downloads/security/q320206/default.asp * Windows NT 4.0 Terminal Server Edition: http://www.microsoft.com/ntserver/terminalserver/downloads/security/Q320206/ default.asp * Windows 2000: http://www.microsoft.com/windows2000/downloads/security/q320206/default.asp Additional information about this patch Installation platforms: * Windows NT 4.0: The Windows NT 4.0 patch can be installed on systems running Service Pack 6a * The Windows NT 4.0 Terminal Server Edition patch can be installed on systems running Windows NT 4.0, Terminal Server Edition Service Pack 6. * Windows 2000: This patch can be installed on systems running Windows 2000 Service Pack 1 or Windows 2000 Service Pack 2 Inclusion in future service packs: The fix for this issue will be included in Windows 2000 Service Pack 3. Reboot needed: Yes Superseded patches: None. Verifying patch installation: Windows NT 4.0 and Windows NT 4.0 Terminal Server Edition: * 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\Windows NT\CurrentVersion\Hotfix\Q320206. * To verify the individual files, consult the file manifest in Knowledge Base article Q320206 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\Q320206. * 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\Q320206\Filelist Caveats: None Localization: Localized versions of this patch are under development. When completed, they will be available at the locations discussed in "Obtaining other security patches". 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 * All patches available via WindowsUpdate also are available in a redistributable form from the WindowsUpdate Corporate site. Other information: Support: * Microsoft Knowledge Base article Q320206 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 (May 22, 2002): Bulletin Created. [***** End Microsoft Security Bulletin MS02-024 *****] _______________________________________________________________________________ CIAC wishes to acknowledge the contributions of Microsoft Corporation for the information contained in this bulletin. _______________________________________________________________________________ CIAC, the Computer Incident Advisory Center, 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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