__________________________________________________________ The U.S. Department of Energy Computer Incident Advisory Capability ___ __ __ _ ___ / | /_\ / \___ __|__ / \ \___ __________________________________________________________ INFORMATION BULLETIN Microsoft Windows Media Services ISAPI Extension Flaw [Microsoft Security Bulletin MS03-019] June 3, 2003 14:00 GMT Number N-100 ______________________________________________________________________________ PROBLEM: Windows Media Services (streaming audio and video) is a feature of Microsoft's Windows 2000 Server, Advanced Server, Datacenter Server, and Windows NT 4.0 Server. It contains support for delivering media content to clients across a network known as multicast streaming. This capability is implemented as an Internet Services Application Programming Interface (ISAPI) extension – nsiislog.dll, and is installed to the Internet Information Services (IIS) Scripts directory on the server. A flaw in the way nsiislog.dll processes incoming requests has been identified. SOFTWARE: Microsoft's Window Media Services only when installed on Windows 2000 or Windows NT 4.0 servers. DAMAGE: By sending specially formed communications to a server running Windows Media Services, an attacker might include code which may cause a Windows 2000 or Windows NT 4.0 server to fail in such a way that could allow code to execute in the security context of the IIS service, or execute code of their choice on a victim's system. SOLUTION: Apply appropriate Microsoft patches as described in MS03-019. ______________________________________________________________________________ VULNERABILITY The risk is HIGH. Windows Media Services is not installed by ASSESSMENT: default, and this high vulnerability risk only applies when it has been installed on Windows 2000 or Windows NT 4.0 servers. The attacker would have to be aware of which server on the network Windows Media Services had been installed on, and was performing logging, in order to cause the server to stop responding to IIS requests. ______________________________________________________________________________ LINKS: CIAC BULLETIN: http://www.ciac.org/ciac/bulletins/n-100.shtml ORIGINAL BULLETIN: http://www.microsoft.com/technet/treeview/default.asp?url= /technet/security/bulletin/MS03-019.asp PATCHES: Microsoft Windows NT 4.0: http://microsoft.com/downloads/details.aspx?FamilyId= 8D7E3716-1AA7-4EDC-B084-7D50C8D3C2AB&displaylang=en Microsoft Windows 2000: http://microsoft.com/downloads/details.aspx?FamilyId= 9EFA4EBD-2068-4742-917D-A2638688C029&displaylang=en ______________________________________________________________________________ [***** Start Microsoft Security Bulletin MS03-019 *****] Microsoft Security Bulletin MS03-019 Flaw in ISAPI Extension for Windows Media Services Could Cause Code Execution (817772) Originally posted: May 28, 2003 Updated: May 30, 2003 Summary Who should read this bulletin: System administrators running Microsoft® Windows NT 4.0 or Microsoft Windows 2000 Impact of vulnerability: Allow an attacker to execute code of their choice Maximum Severity Rating: Important Recommendation: System administrators install the patch at the earliest available opportunity. Affected Software: Microsoft Windows NT 4.0 Microsoft Windows 2000 Non Affected Software: Microsoft Windows XP Microsoft Windows Server 2003 Technical details Technical description: On May 28th, Microsoft released the initial version of this bulletin, rating the severity of the vulnerability as Moderate. Subsequent to that release we have determined that the actions an attacker could take as a result of exploiting this vulnerability could include the ability to execute arbitrary code. As a result Microsoft has reissued this bulletin and changed the severity rating to Important. The original patch corrects the vulnerability and is not being re-released. Microsoft Windows Media Services is a feature of Microsoft Windows 2000 Server, Advanced Server, and Datacenter Server and is also available as a downloadable version for Windows NT 4.0 Server. Windows Media Services contain support for a method of delivering media content to clients across a network known as multicast streaming. In multicast streaming however, the server has no connection or knowledge of the clients that may be receiving the stream coming from the server. To facilitate logging of client information for the server Windows 2000 includes a capability specifically designed for that purpose. To help with this problem, Windows 2000 includes logging capabilities for multicast and unicast transmissions. This capability is implemented as an Internet Services Application Programming Interface (ISAPI) extension – nsiislog.dll. When Windows Media Services are installed in Windows NT 4.0 Server or added through add/remove programs to Windows 2000, nsiislog.dll is installed to the Internet Information Services (IIS) Scripts directory on the server. There is a flaw in the way in which nsiislog.dll processes incoming requests. A vulnerability exists because an attacker could send specially formed communications to the server that could cause IIS to fail or execute code on the user's system. Windows Media Services is not installed by default on Windows 2000, and must be downloaded to install on Windows NT 4.0. An attacker attempting to exploit this vulnerability would have to be aware which computers on the network had Windows Media Services installed on it and send a specific request to that server. Mitigating factors: Windows Media Services 4.1 is not installed by default on Windows 2000, and must be downloaded to install on Windows NT 4.0. Windows Media Services are not available for Windows 2000 Professional or Windows NT 4.0 Workstation The attacker would have to know which server on the network Windows Media Services had been installed on. Severity Rating: Windows NT 4.0 Important 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-2003-0227 Tested Versions: Microsoft tested Windows NT 4.0, 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 NT 4.0: http://microsoft.com/downloads/details.aspx?FamilyId= 8D7E3716-1AA7-4EDC-B084-7D50C8D3C2AB&displaylang=en Microsoft Windows 2000: http://microsoft.com/downloads/details.aspx?FamilyId= 9EFA4EBD-2068-4742-917D-A2638688C029&displaylang=en Additional information about this patch Installation platforms: The Windows NT 4.0 patch can be installed on systems running Service Pack 6a. The Windows 2000 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: No. Patch can be uninstalled: No. 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 Media Services\wm817772 To verify the individual files, use the date/time and version information provided in Knowledge Base article 817772. 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 Brett Moore for reporting this issue to us and working with us to protect customers. Support: Microsoft Knowledge Base article 817772 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 28, 2003: Bulletin Created. V2.0 May 30, 2003: Re-released bulletin with new rating of Important to reflect additional action an attacker could take. [***** End Microsoft Security Bulletin MS03-019 *****] _______________________________________________________________________________ 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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