N-001: Microsoft File Decompression Functions Vulnerabilities

[***** 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 *****]

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