__________________________________________________________ The U.S. Department of Energy Computer Incident Advisory Capability ___ __ __ _ ___ / | /_\ / \___ __|__ / \ \___ __________________________________________________________ INFORMATION BULLETIN Vulnerability in TNEF Decoding in Microsoft Outlook and Microsoft Exchange Could Allow Remote Code Execution [Microsoft Security Bulletin MS06-003 (902412)] January 10, 2006 23:00 GMT Number Q-096 ______________________________________________________________________________ PROBLEM: A remote code execution vulnerability exists in Microsoft Outlook and Microsoft Exchange Server because of the way that it decodes the Transport Neutral Encapsulation Format (TNEF) MIME attachment. PLATFORM: Microsoft Office 2000 Service Pack 3 Microsoft Office XP Service Pack 3 Microsoft Office 2003 Service Pack 1 and Service Pack 2 Microsoft Exchange Server DAMAGE: An attacker could exploit the vulnerability by constructing a specially crafted TNEF message that could potentially allow remote code execution when a user opens or previews a malicious e-mail message or when the Microsoft Exchange Server Information Store processes the specially crafted message. SOLUTION: Apply current patches. ______________________________________________________________________________ VULNERABILITY The risk is HIGH. Remote Code Execution and possible root ASSESSMENT: compromise. ______________________________________________________________________________ LINKS: CIAC BULLETIN: http://www.ciac.org/ciac/bulletins/q-096.shtml ORIGINAL BULLETIN: http://www.microsoft.com/technet/security/Bulletin/MS06- 003.mspx CVE: http://www.cve.mitre.org/cgi-bin/cvename.cgi?name= CVE-2006-0002 ______________________________________________________________________________ [***** Start Microsoft Security Bulletin MS06-003 (902412) *****] Microsoft Security Bulletin MS06-003 Vulnerability in TNEF Decoding in Microsoft Outlook and Microsoft Exchange Could Allow Remote Code Execution (902412) Published: January 10, 2006 Version: 1.0 Summary Who should read this document: Customers who use Microsoft Outlook, Microsoft Exchange, or customers who have the Microsoft Office Multilingual User Interface (MUI) Packs, Microsoft Multilanguage Packs or Microsoft Office 2003 Language Interface Packs (LIPS) installed. Impact of Vulnerability: Remote Code Execution Maximum Severity Rating: Critical Recommendation: Customers should apply the update immediately. Security Update Replacement: None Caveats: None Tested Software and Security Update Download Locations: Affected Software: • Microsoft Office 2000 Service Pack 3 Microsoft Office 2000 Software: • Microsoft Outlook 2000 – Download the update (KB892842) • Microsoft Office 2000 MultiLanguage Packs – Download the update (KB892842) • Microsoft Outlook 2000 English MultiLanguage Packs – Download the update (KB892842) • Microsoft Office XP Service Pack 3 Microsoft Office XP Software: • Microsoft Outlook 2002 – Download the update (KB892841) • Microsoft Office XP Multilingual User Interface Packs – Download the update (KB892841) Note Multilingual User Interface Packs are for non- English packages. • Microsoft Office 2003 Service Pack 1 and Service Pack 2 Microsoft Office 2003 Software: • Microsoft Outlook 2003 – Download the update (KB892843) • Microsoft Office 2003 Multilingual User Interface Packs – Download the update (KB892843) • Microsoft Office 2003 Language Interface Packs – Download the update (KB887617) Note Multilingual User Interface Packs are for non- English packages • Microsoft Exchange Server • Microsoft Exchange Server 5.0 Service Pack 2 – Download the update (KB894689) • Microsoft Exchange Server 5.5 Service Pack 4– Download the update (KB894689) • Microsoft Exchange 2000 Server Pack 3 with the Exchange 2000 Post-Service Pack 3 Update Rollup of August 2004 – Download the update (894689) Non-Affected Software: • Microsoft Exchange Server 2003 Service Pack 1 • Microsoft Exchange Server 2003 Service Pack 2 The software in this list has been tested to determine whether the versions are affected. Other versions either no longer include security update support or may not be affected. To determine the support life cycle for your product and version, visit the Microsoft Support Lifecycle Web site. For more information about Exchange 2000 Server Post-Service Pack 3 Update Rollup see Microsoft Knowledge Base Article 870540. Top of sectionTop of section General Information Executive Summary Executive Summary: This update resolves a newly-discovered, privately-reported vulnerability that could allow an attacker to run arbitrary code on the system. The vulnerability is documented in the “Vulnerability Details” section of this bulletin. On vulnerable versions of Outlook, Office Language Interface Packs, Office MultiLanguage Packs or Office Multilingual User Interface Packs, if a user is logged on with administrative user rights, an attacker who successfully exploited this vulnerability could take complete control of the client workstation. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights. Users whose accounts are configured to have fewer user rights on the system could be less impacted than users who operate with administrative user rights. On vulnerable versions of Exchange, an attacker who successfully exploited this vulnerability could take complete control of an affected system. This vulnerability could be exploited automatically without user interaction. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights. We recommend that customers apply the update immediately. Severity Ratings and Vulnerability Identifiers: Vulnerability Identifiers Impact of Vulnerability Outlook 2000, Outlook 2002, Outlook 2003 Office 2000 MultiLanguage Packs (MUI), Office XP Multilingual User Interface Packs (MUI), Office 2003 Multilingual User Interface Packs (MUI) or Office 2003 Language Interface Packs (LIP) Exchange Server 5.0, Exchange Server 5.5, Exchange 2000 Server TNEF Decoding Vulnerability - CVE-2006-0002 Remote Code Execution Critical Critical Critical This assessment is based on the types of systems that are affected by the vulnerability, their typical deployment patterns, and the effect that exploiting the vulnerability would have on them. Top of sectionTop of section Vulnerability Details TNEF Decoding Vulnerability - CVE-2006-0002 A remote code execution vulnerability exists in Microsoft Outlook and Microsoft Exchange Server because of the way that it decodes the Transport Neutral Encapsulation Format (TNEF) MIME attachment. An attacker could exploit the vulnerability by constructing a specially crafted TNEF message that could potentially allow remote code execution when a user opens or previews a malicious e-mail message or when the Microsoft Exchange Server Information Store processes the specially crafted message. An attacker who successfully exploited this vulnerability could take complete control of an affected system. Mitigating Factors for TNEF Decoding Vulnerability - CVE-2006-0002: • Users whose accounts are configured to have fewer user rights on the system could be less impacted than users who operate with administrative user rights. Top of sectionTop of section Workarounds for TNEF Decoding Vulnerability - CVE-2006-0002: Microsoft has tested the following workarounds. While these workarounds will not correct the underlying vulnerability, they help block known attack vectors. When a workaround reduces functionality, it is identified in the following section. • Block MS-TNEF on Microsoft Exchange Server to help protect against attempts to exploit this vulnerability through SMTP e-mail. Systems can be configured to block certain types of files from being received as e-mail attachments. Microsoft TNEF-encoded e-mail messages, commonly known as rich text format (RTF) e-mail messages, can contain malicious OLE objects. These e-mail messages contain a file attachment that stores the TNEF information. This file attachment is usually named Winmail.dat. Blocking this file, and blocking the ms-tnef MIME type, could help protect Exchange servers and other affected programs from attempts to exploit this vulnerability if customers cannot install the available security update. To help protect an Exchange Server computer from attacks through SMTP, block the Winmail.dat file and all application /ms-tnef MIME type content before it reaches the Exchange Server computer. Note You cannot mitigate this vulnerability by setting the Exchange rich-text format option in Exchange Server to Never used or by disabling TNEF processing by editing the registry. Note Exchange supports other messaging protocols, such as X.400, that these workarounds do not protect. We recommend that administrators require authentication on all other client and message transport protocols to help prevent attacks using these protocols. Note Filtering only for attachments that have the file name Winmail.dat may not be sufficient to help protect your system. A malicious file attachment could be given another file name that could then be processed by the Exchange Server computer. To help protect against malicious e-mail message’s, block all application/ms-tnef MIME type content. There are many ways to block the Winmail.dat file and other TNEF content. Here are some suggestions: • You can use ISA Server 2000 SMTP Message Screener to block all file attachments or to block only the Winmail.dat file. Blocking all file attachments provides the most protection for this issue if you use ISA Server 2000 because ISA Server 2000 does not support blocking content based on MIME content types. For more information, see Microsoft Knowledge Base Article 315132. • You can use ISA Server 2000 SMTP Filter to block all file attachments or to block only the Winmail.dat file. Blocking all file attachments provides the most protection for this issue if you use ISA Server 2000 because ISA Server 2000 does not support blocking content based on MIME content types. For more information, see Microsoft Knowledge Base Article 320703. • You can use ISA Server 2004 SMTP Filter and Message Screener block all file attachments or just the Winmail.dat file. Blocking all file attachments provides the most protection for this issue if you use ISA Server 2004 because ISA Server 2004 does not support blocking content based on MIME content types. For more information, see Microsoft Knowledge Base Article 888709. • You can use third-party e-mail filters to block all application/ms-tnef MIME type content before it is sent to the Exchange Server computer or to a vulnerable application. Impact of workaround: If TNEF attachments are blocked, e-mail messages that are formatted as RTF will not be received correctly. In some cases, users could receive blank e-mail messages instead of the original RTF-formatted e-mail message. In other cases, users may not receive e-mail messages that are formatted as RTF at all. Blocking the TNEF attachments will not affect e-mail messages that are formatted as HTML or that are formatted as plain text. Perform this workaround only if you cannot install the available security update or if a security update is not publicly available for your configuration. • Require authentication for connections to a server that is running Microsoft Exchange Server for all client and message transport protocols. Requiring authentication for all connections made to the Exchange Server computer will help protect against anonymous attacks. This will not protect against an attack from a malicious user who can successfully authenticate. Impact of workaround: Anonymous communication from clients through IMAP, POP3, HTTP, LDAP, SMTP, and NNTP will no longer be possible. Server to server anonymous communication through RPC, X.400, foreign gateway, and third-party connector protocols will also no longer be possible. In most configurations of Exchange Server, authenticated access is already required for all protocols except SMTP. If all application/ms-tnef MIME type message parts and the Winmail.dat file are blocked, as described in the previous workaround, anonymous SMTP connections could still be accepted. • Do not accept incoming public newsfeeds through the NNTP protocol on Microsoft Exchange Server. Incoming newsfeeds are not enabled by default for Exchange Server. If you have subscribed to incoming newsfeeds from public newsgroups, an attacker could post a malicious message to such a newsgroup. Even if you require authentication between the news server and your Exchange Server computer, such a message could still be transferred to your Exchange Server computer. Therefore, you should disable incoming newsfeeds from any NNTP server that could let a user post a malicious message. Impact of workaround: Exchange access to public newsgroup feeds will no longer be possible. Acknowledgments Microsoft thanks the following for working with us to help protect customers: • John Heasman and Mark Litchfield of NGS Software for reporting the TNEF Decoding Vulnerability - CVE-2006-0002 Obtaining Other Security Updates: Updates for other security issues are available at the following locations: • Security updates are available in the Microsoft Download Center. You can find them most easily by doing a keyword search for "security_patch." • Updates for consumer platforms are available at the Microsoft Update Web site. Support: • Customers in the U.S. and Canada can receive technical support from Microsoft Product Support Services at 1-866-PCSAFETY. There is no charge for support calls that are associated with security updates. • International customers can receive support from their local Microsoft subsidiaries. There is no charge for support that is associated with security updates. For more information about how to contact Microsoft for support issues, visit the International Support Web site. Security Resources: • The Microsoft TechNet Security Web site provides additional information about security in Microsoft products. • Microsoft Software Update Services • Microsoft Windows Server Update Services • Microsoft Baseline Security Analyzer (MBSA) • Windows Update • Microsoft Update • Windows Update Catalog: For more information about the Windows Update Catalog, see Microsoft Knowledge Base Article 323166. • Office Update Software Update Services: By using Microsoft Software Update Services (SUS), administrators can quickly and reliably deploy the latest critical updates and security updates to Windows 2000 and Windows Server 2003-based servers, and to desktop systems that are running Windows 2000 Professional or Windows XP Professional. For more information about how to deploy security updates by using Software Update Services, visit the Software Update Services Web site. Windows Server Update Services: By using Windows Server Update Services (WSUS), administrators can quickly and reliably deploy the latest critical updates and security updates for Windows 2000 operating systems and later, Office XP and later, Exchange Server 2003, and SQL Server 2000 onto Windows 2000 and later operating systems. For more information about how to deploy security updates using Windows Server Update Services, visit the Windows Server Update Services Web site. Systems Management Server: Microsoft Systems Management Server (SMS) delivers a highly-configurable enterprise solution for managing updates. By using SMS, administrators can identify Windows-based systems that require security updates and can perform controlled deployment of these updates throughout the enterprise with minimal disruption to end users. For more information about how administrators can use SMS 2003 to deploy security updates, visit the SMS 2003 Security Patch Management Web site. SMS 2.0 users can also use Software Updates Service Feature Pack to help deploy security updates. For information about SMS, visit the SMS Web site. Note SMS uses the Microsoft Baseline Security Analyzer, the Microsoft Office Detection Tool, and the Enterprise Update Scanning Tool to provide broad support for security bulletin update detection and deployment. Some software updates may not be detected by these tools. Administrators can use the inventory capabilities of the SMS in these cases to target updates to specific systems. For more information about this procedure, visit the following Web site. Some security updates require administrative rights following a restart of the system. Administrators can use the Elevated Rights Deployment Tool (available in the SMS 2003 Administration Feature Pack and in the SMS 2.0 Administration Feature Pack) to install these updates. 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 (January 10, 2006): Bulletin published. [***** End Microsoft Security Bulletin MS06-003 (902412) *****] _______________________________________________________________________________ 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. 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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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