__________________________________________________________ The U.S. Department of Energy Computer Incident Advisory Center ___ __ __ _ ___ / | /_\ / \___ __|__ / \ \___ __________________________________________________________ INFORMATION BULLETIN MS Exchange - Incorrectly Sets Remote Registry Permissions [Microsoft Security Bulletin MS02-003] February 8, 2002 17:00 GMT Number M-040 ______________________________________________________________________________ PROBLEM: There is a flaw in how the System Attendant makes changes to the Registry configuration. PLATFORM: Microsoft Exchange Server 2000 DAMAGE: This flaw could allow an attacker remote access to configuration information on the server. SOLUTION: Apply available patch. ______________________________________________________________________________ VULNERABILITY The risk is LOW. This vulnerability does not itself give an ASSESSMENT: attacker the ability to change Registry settings. It could be used in conjunction with inappropriately permissive registry settings to gain access to, and make changes to a systems Registry. ______________________________________________________________________________ LINKS: CIAC BULLETIN: http://www.ciac.org/ciac/bulletins/m-040.shtml ORIGINAL BULLETIN: http://www.microsoft.com/technet/treeview/ default.asp?url=/technet/security/bulletin/ MS02-003.asp PATCHES: http://www.microsoft.com/downloads/ release.asp?ReleaseID=35462 ______________________________________________________________________________ [***** Start Microsoft Security Bulletin MS02-003 *****] Microsoft Security Bulletin MS02-003 Exchange 2000 System Attendant Incorrectly Sets Remote Registry Permissions Originally posted: February 07, 2002 Summary Who should read this bulletin: System administrators using Microsoft® Exchange 2000. Impact of vulnerability: Less Secure Default Settings. Maximum Severity Rating: Low Recommendation: Administrators should apply the patch. Affected Software: * Microsoft Exchange Server 2000 Technical details Technical description: The Microsoft Exchange System Attendant is one of the core services in Microsoft Exchange. It performs a variety of functions related to the on-going maintenance of the Exchange system. To allow remote administration of an Exchange Server using the Exchange System Manager Microsoft Management Console (MMC) snap in, the System Attendant makes changes to the permissions on the Windows Registry to allow Exchange Administrators to remotely update configuration settings stored in the Registry. There is a flaw in how the System Attendant makes these Registry configuration changes. This flaw could allow an unprivileged user to remotely access configuration information on the server. Specifically, this flaw inappropriately gives the "Everyone" group privileges to the WinReg key. This key controls the ability of users and groups to remotely connect to the Registry. By default, only Administrators are given the ability to remotely connect to the Registry, by granting permissions on this key. The flaw does not grant any abilities beyond the ability to connect remotely. However, an attacker's ability to make changes to the Registry once they have successfully connected would be dictated by the permissions on the specific keys within the Registry itself. Thus, while this vulnerability does not itself give an attacker the ability to change Registry settings, it could be used in conjunction with inappropriately permissive registry settings to gain access to, and make changes to a systems Registry. Mitigating factors: * The vulnerability only grants the ability to connect to the Registry remotely. It does not weaken any other permissions in the Registry. * An attacker's ability to connect to the Registry remotely requires the ability to send SMB traffic to and from the target system. Firewalling best practices recommends closing the ports that NetBIOS and Direct Host uses (tcp ports 139 and 445) Severity Rating: Internet Servers Intranet Servers Client Systems Exchange 2000 Server Low Low None 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. For Internet exposed systems, the best practices of blocking tcp ports 139 and 445 at the firewall prevents remote access to the registry. While there is a potential for allowing data to be compromised, there are significant mitigating factors. Vulnerability identifier: CAN-2002-0049 Tested Versions: Microsoft tested Exchange 5.5 and Exchange 2000 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 Exchange Server 2000: http://www.microsoft.com/downloads/release.asp?ReleaseID=35462 Additional information about this patch Installation platforms: This patch can be installed on systems running Microsoft Exchange 2000 SP2. Inclusion in future service packs: The fix for this issue will be included in Microsoft Exchange 2000 SP3. Reboot needed: 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\Exchange Server 2000\SP3\Q316056. * To verify the individual files, use the date/time and version information provided in the following registry key: HKEY_LOCAL_MACHINE \Software\Microsoft\ Updates\Exchange Server 2000\SP3\Q316056\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: Acknowledgments Microsoft thanks Eitan Caspi for reporting this issue to us and working with us to protect customers. Support: * Microsoft Knowledge Base article Q316056 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 (February 07, 2002): Bulletin Created. [***** End Microsoft Security Bulletin MS02-003 *****] _______________________________________________________________________________ CIAC wishes to acknowledge the contributions of Microsoft 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. 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