__________________________________________________________ The U.S. Department of Energy Computer Incident Advisory Capability ___ __ __ _ ___ / | /_\ / \___ __|__ / \ \___ __________________________________________________________ INFORMATION BULLETIN Microsoft Network Connection Manager (NCM) Flaw Could Enable Privilege Elevation [Microsoft Security Bulletin MS02-042] August 19, 2002 17:00 GMT Number M-113 ______________________________________________________________________________ PROBLEM: The NCM provides a controlling mechanism for all network connections managed by a host system using handler routines. It is possible for an unprivileged user to configure the handler routine used by the (NCM) when a new network connection is established. PLATFORM: Microsoft Windows 2000 DAMAGE: An attacker who successfully exploits this vulnerability could gain the ability to take actions such as adding, deleting, modifying data on the system, creating or deleting user accounts, and adding accounts to the local administrators group. SOLUTION: Apply available patches. ______________________________________________________________________________ VULNERABILITY The risk is LOW. To exploit this vulnerability, an attacker ASSESSMENT: would need credentials to log onto the computer interactively. Best practices suggest that unprivileged users not be allowed to interactively log onto business-critical servers. If this guidance has been followed, such servers would not be at risk. ______________________________________________________________________________ LINKS: CIAC BULLETIN: http://www.ciac.org/ciac/bulletins/m-113.shtml ORIGINAL BULLETIN: http://www.microsoft.com/technet/treeview/default.asp?url=/technet/security/bulletin/MS02-042.asp PATCHES: http://www.microsoft.com/downloads/Release.asp?ReleaseID=41406 ______________________________________________________________________________ [***** Start Microsoft Security Bulletin MS02-042 *****] Originally posted: August 14, 2002 Summary Who should read this bulletin: Customers using Microsoft® Windows® 2000. Impact of vulnerability: Privilege elevation Maximum Severity Rating: Critical Recommendation: Administrators should apply the patch to immediately to machines that allow unprivileged users to log onto them interactively such as workstations and Terminal Servers. Affected Software: Microsoft Windows 2000 Technical details Technical description: The Network Connection Manager (NCM) provides a controlling mechanism for all network connections managed by a host system. Among the functions of the NCM is to call a handler routine whenever a network connection has been established. By design, this handler routine should run in the security context of the user. However, a flaw could make it possible for an unprivileged user to cause the handler routine to run in the security context of LocalSystem, though a very complex process. An attacker who exploited this flaw could specify code of his or her choice as the handler, then establish a network connection in order to cause that code to be invoked by the NCM. The code would then run with full system privileges. Mitigating factors: The vulnerability could only be exploited by an attacker who had the appropriate credentials to log onto an affected system interactively. Best practices suggests that unprivileged users not be allowed to interactively log onto business-critical servers. If this recommendation has been followed, machines such as domain controllers, ERP servers, print and file servers, database servers, and others would not be at risk from this vulnerability. Severity Rating: Internet Servers Intranet Servers Client Systems Windows 2000 Low Critical 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. Vulnerability identifier: CAN-2002-0720 Tested Versions: Microsoft tested Windows XP, Windows 2000 and Windows NT 4.0 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://www.microsoft.com/downloads/Release.asp?ReleaseID=41406 Additional information about this patch Installation platforms: This patch can be installed on systems running Windows 2000 Service Pack 2 or Service Pack 3. Inclusion in future service packs: The fix for this issue will be included in Windows 2000 Service Pack 4. Reboot needed: Yes Patch can be uninstalled: Yes Superseded patches: None. Verifying patch installation: 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\Q326886. 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\Q326886\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: Support: Microsoft Knowledge Base article Q326886 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 (August 14, 2002): Bulletin Created. [***** End Microsoft Security Bulletin MS02-042 *****] _______________________________________________________________________________ CIAC wishes to acknowledge the contributions of Microsoft 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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