__________________________________________________________ The U.S. Department of Energy Computer Incident Advisory Center ___ __ __ _ ___ / | /_\ / \___ __|__ / \ \___ __________________________________________________________ INFORMATION BULLETIN Microsoft Outlook E-mail Editor Vulnerability [Microsoft Security Bulletin MS02-021] April 26, 2002 15:00 GMT Number M-073 ______________________________________________________________________________ PROBLEM: A security vulnerability exists when Outlook is configured to use Microsoft Word as the e-mail editor and the user forwards or replies to a mail from an attacker. PLATFORM: Systems using the following applications for e-mail: Microsoft Outlook 2000 Microsoft Outlook 2002 DAMAGE: An attacker could exploit this vulnerability by sending a specially malformed HTML e-mail containing a script to an Outlook user who has Word enabled as the e-mail editor. If the user replied to or forwarded the e-mail, the script would then run, and be capable of taking any action the user could take. SOLUTION: Apply the patch supplied by vendor. ______________________________________________________________________________ VULNERABILITY The risk is MEDIUM. For an attacker to successfully exploit ASSESSMENT: this vulnerability, the user would need to reply to or forward the malicious e-mail. Simply reading it would not enable the scripts to run, and the user could delete the mail without risk. ______________________________________________________________________________ LINKS: CIAC BULLETIN: http://www.ciac.org/ciac/bulletins/m-073.shtml ORIGINAL BULLETIN: http://www.microsoft.com/technet/treeview/default.asp?url=/technet/security/bulletin/MS02-021.asp ______________________________________________________________________________ [***** Start Microsoft Security Bulletin MS02-021 *****] Microsoft Security Bulletin MS02-021 E-mail Editor Flaw Could Lead to Script Execution on Reply or Forward (Q321804) Originally posted: April 25, 2002 Summary Who should read this bulletin: Users of Microsoft® Outlook 2000 or Outlook 2002 Impact of vulnerability: Run Code of Attacker's Choice Maximum Severity Rating: Moderate Recommendation: Customers using WordMail should apply the patch immediately Affected Software: Microsoft Outlook 2000 Microsoft Outlook 2002 Technical details Technical description: Outlook 2000 and 2002 provide the option to use Microsoft Word as the e-mail editor when creating and editing e-mail in either Rich-Text or HTML format. A security vulnerability exists when Outlook is configured this way and the user forwards or replies to a mail from an attacker. The vulnerability results from a difference in the security settings that are applied when displaying a mail versus editing one. When Outlook displays an HTML e-mail, it applies Internet Explorer security zone settings that disallow scripts from being run. However, if the user replies to or forwards a mail message and has selected Word as the e-mail editor, Outlook opens the mail and puts the Word editor into a mode for creating e-mail messages. Scripts are not blocked in this mode. An attacker could exploit this vulnerability by sending a specially malformed HTML e-mail containing a script to an Outlook user who has Word enabled as the e-mail editor. If the user replied to or forwarded the e-mail, the script would then run, and be capable of taking any action the user could take. Mitigating factors: The vulnerability only affects Outlook users who use Word as their e-mail editor. Users who have enabled the feature introduced in Office XP SP1 to read HTML mail as plain text are not vulnerable. For an attacker to successfully exploit this vulnerability, the user would need to reply to or forward the malicious e-mail. Simply reading it would not enable the scripts to run, and the user could delete the mail without risk. Severity Rating: Internet Servers Intranet Servers Client Systems Outlook 2000 None None Moderate Outlook 2002 None None Moderate 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 e-mail recipient must be using Word as their e-mail editor and choose to reply to or forward a specially malformed HTML e-mail received from an attacker. Vulnerability identifier: CAN-2002-1056 Tested Versions: Microsoft tested Outlook 2000 and Outlook 2002 to assess whether they are affected by this vulnerability. Previous versions are no longer supported, and may or may not be affected by these vulnerabilities. Patch availability Download locations for this patch Microsoft Word 2002: Client Installation: http://office.microsoft.com/downloads/2002/wrd1003.aspx Administrative Installation: http://www.microsoft.com/office/ork/xp/journ/wrd1003a.htm Microsoft Word 2000: Client Installation: http://office.microsoft.com/downloads/2002/wrd0901.aspx Administrative Installation: http://www.microsoft.com/office/ork/xp/journ/wrd0901a.htm Additional information about this patch Installation platforms: This patch can be installed on systems running Office 2000 SR-1 or greater or Office XP SP-1 or greater. Inclusion in future service packs: The fix for this issue will be included in any future service packs for Office Reboot needed: No. Superseded patches: None. Verifying patch installation: Word 2002: Verify that the version number of Winword.exe is 10.4009.3501 Word 2000: Verify that the version number of Winword.exe is 9.0.6328 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 Q321804 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 (April 25, 2002): Bulletin Created. [***** End Microsoft Security Bulletin MS02-021 *****] _______________________________________________________________________________ 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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