__________________________________________________________ The U.S. Department of Energy Computer Incident Advisory Capability ___ __ __ _ ___ / | /_\ / \___ __|__ / \ \___ __________________________________________________________ INFORMATION BULLETIN Microsoft File Decompression Functions Vulnerabilities [Microsoft Security Bulletin MS02-054] October 3, 2002 18:00 GMT Number N-001 ______________________________________________________________________________ PROBLEM: An unchecked buffer exists in the programs that handle the decompressing of files from a zipped file. The decompression function could place a file in a directory that was not the same as, or child of, the target directory specified by the user. PLATFORM: Microsoft Windows 98 with Plus! Pack Microsoft Windows ME Microsoft Windows XP DAMAGE: Attempts to open a file with a specially malformed filename contained in a zipped file could allow code of an attacker's choice to be run. Attackers could place files in locations of his/her choice such as in a startup directory. SOLUTION: Apply available patches. ______________________________________________________________________________ VULNERABILITY The risk is LOW. The most serious vulnerability could allow an ASSESSMENT: attacker to potentially run code of his/her choice. The vulnerabilities could not be exploited without user intervention. The attacker would need to entice the user to receive, store, and open the zipped file provided by the attacker. ______________________________________________________________________________ LINKS: CIAC BULLETIN: http://www.ciac.org/ciac/bulletins/n-001.shtml ORIGINAL BULLETIN: http://www.microsoft.com/technet/treeview/default.asp?url= /technet/security/bulletin/MS02-054.asp PATCHES: - Windows 98 with Plus! Pack: http://www.microsoft.com/windows98/downloads/contents/ WUCritical/q329048/default.asp - Windows ME: Only available via http://windowsupdate.microsoft.com/ - Windows XP: http://www.microsoft.com/Downloads/Release.asp? ReleaseID=43419 ______________________________________________________________________________ [***** Start Microsoft Security Bulletin MS02-054 *****] Microsoft Security Bulletin MS02-054 Unchecked Buffer in File Decompression Functions Could Lead to Code Execution (Q329048) Originally posted: October 02, 2002 Summary Who should read this bulletin: Customers using Microsoft® Windows® 98 with Plus! Pack, Windows Me, or Windows XP Impact of vulnerability: Two vulnerabilities, the most serious of which could run code of attacker’s choice Maximum Severity Rating: Moderate Recommendation: Consider applying the patch to affected systems Affected Software: Microsoft Windows 98 with Plus! Pack Microsoft Windows Me Microsoft Windows XP Technical details Technical description: Zipped files (files having a .zip extension) provide a means to store information in a way that uses less space on a hard disk. This is accomplished by compressing the files that are put into in the zipped file. On Windows 98 with Plus! Pack, Windows Me and Windows XP, the Compressed Folders feature allows zipped files to be treated as folders. The Compressed Folders feature can be used to create, add files to, and extract files from zipped files. Two vulnerabilities exist in the Compressed Folders function: An unchecked buffer exists in the programs that handles the decompressing of files from a zipped file. A security vulnerability results because attempts to open a file with a specially malformed filename contained in a zipped file could possibly result in Windows Explorer failing, or in code of the attacker’s choice being run. The decompression function could place a file in a directory that was not the same as, or a child of, the target directory specified by the user as where the decompressed zip files should be placed. This could allow an attacker to put a file in a known location on the users system, such as placing a program in a startup directory Mitigating factors: The vulnerabilities could not be exploited without user intervention. The attacker would need to entice the user to receive, store, and open the zipped file provided by the attacker. The vulnerabilities could not be exploited remotely. An attacker would need to lure a user into receiving the zipped file onto the user’s machine. Best practices suggest users not accept e-mail attachments from people who are not trusted, and not to download files from untrusted Internet sites. On Windows 98 and Windows Me, the Compressed Folders feature is not installed by default. Users who had not installed this feature would not be vulnerable. Severity Rating: Unchecked Buffer in Zipped File Handling Internet Servers Intranet Servers Client Systems Microsoft Windows 98 with Low Low Moderate PLUS! Pack Microsoft Windows Me Low Low Moderate Microsoft Windows XP Low Low Moderate Incorrect Target Path for Zipped File Decompression Internet Servers Intranet Servers Client Systems Microsoft Windows 98 with Low Low Moderate PLUS! Pack Microsoft Windows Me Low Low Moderate Microsoft Windows XP Low Low 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. For this vulnerability to be exploited, a user would have to receive a zipped file from an attacker, store it locally, and attempt to decompress the zipped file. Vulnerability identifiers: Unchecked Buffer in Zipped File Handling: CAN-2002-0370 Incorrect Target Path for Zipped File Decompression: CAN-2002-1139 Tested Versions: Microsoft tested Microsoft Windows XP, Windows ME, and Windows 98 with Plus! Pack to assess whether they are affected by this vulnerability. Microsoft Windows NT 4.0 and Windows 2000 do not have the affected feature. Previous versions are no longer supported, and may or may not be affected by these vulnerabilities. Patch availability Download locations for this patch Windows 98 with Plus! Pack: http://www.microsoft.com/windows98/downloads/contents/WUCritical/q329048/ default.asp Windows Me: Only available via Windows Update. Windows XP: http://www.microsoft.com/Downloads/Release.asp?ReleaseID=43419 Additional information about this patch Installation platforms: This patch can be installed on systems running Windows 98 or Windows 98 Second Edition. This patch can be installed on systems running Windows Millennium Edition. This patch can be installed on systems running Windows XP Gold and Windows XP Service Pack 1. Inclusion in future service packs: The fix for these issues will be included in Windows XP Service Pack 2. The fix for Unchecked Buffer in Zipped File Handling is also included in Windows XP Service Pack 1. Reboot needed: Windows 98: Yes Windows Me: Yes Windows XP: Yes Patch can be uninstalled: Windows 98: Yes Windows Me: Yes Windows XP: Yes Superseded patches: None. Verifying patch installation: Windows 98 with Plus! Pack: To verify that the patch has been installed, perform the following steps: Execute the QFECHECK program using Start – Run Expand the W98 tree (click on the + next to W98) Look for the string "Q329048" (without the quotes) Windows Me: To verify that the patch has been installed, perform the following steps: Execute the QFECHECK program using Start – Run Expand WINME tree (click on the + next to WinME) Look for the string "Q329048" (without the quotes) Windows XP: To verify that the patch has been installed, confirm that the following registry key has been created on the machine: HKLM\Software\Microsoft\Updates\Windows XP\SP2\Q329048 To verify the individual files, use the date/time and version information provided in the following registry key: HKLM\Software\Microsoft\Updates\Windows XP\SP2\Q329048\Filelist Caveats: None Localization: Localized versions of this patch are 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 the following people for working with us to protect customers: Joe Testa of Rapid7, Inc. (http://www.rapid7.com/) for reporting the Unchecked Buffer in Zipped File Handling vulnerability. zen-parse for reporting the Incorrect Target Path for Zipped File Decompression vulnerability. Support: Microsoft Knowledge Base article Q329048 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 (October 02, 2002): Bulletin Created. [***** End Microsoft Security Bulletin MS02-054 *****] _______________________________________________________________________________ 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. 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