Microsoft KB Archive/322296

= MS02-026: Unchecked Buffer in ASP.NET Worker Process (Spanish) =

PSS ID Number: 322296

Article Last Modified on 4/21/2003

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The information in this article applies to:


 * Microsoft ASP.NET (included with the .NET Framework) 1.0
 * Microsoft .NET Framework

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This article was previously published under Q322296



SYMPTOMS
A buffer overrun vulnerability exists in Microsoft ASP.NET. An attacker who was able to successfully exploit this vulnerability could cause the application that is running on the Web server to restart. Additionally, although Microsoft has not been able to demonstrate it, an attacker could exploit this vulnerability to cause code to run on the Web server. The code could run in the security context of the ASP.NET worker process (Aspnet_wp.exe), which uses an unprivileged account by default.

This vulnerability affects only ASP.NET applications that use StateServer mode to manage session state information. StateServer mode is not the default mode. Finally, this vulnerability affects only those applications that use StateServer mode and that also use cookies. This vulnerability does not affect applications that use StateServer mode without cookies.



CAUSE
This vulnerability occurs because a function that processes cookie data in the ASPState service cannot properly check the length of the cookies that are passed to it.



RESOLUTION
A supported fix is now available from Microsoft, but it is only intended to correct the problem that is described in this article. Apply it only to computers that you determine are at risk of attack. Evaluate your computer's physical accessibility, network and Internet connectivity, and other factors to determine the degree of risk to your computer. See the associated Microsoft Security Bulletin to help determine the degree of risk. This fix may receive additional testing. If your computer is sufficiently at risk, Microsoft recommends that you apply this fix now. Otherwise, wait for the next Microsoft .NET Framework service pack that contains this fix.

To resolve this problem immediately, download the fix by following the instructions later in this article or contact Microsoft Product Support Services to obtain the fix. For a complete list of Microsoft Product Support Services phone numbers and information about support costs, visit the following Microsoft Web site:

http://support.microsoft.com/default.aspx?scid=fh;EN-US;CNTACTMS

NOTE: In special cases, charges that are ordinarily incurred for support calls may be canceled if a Microsoft Support Professional determines that a specific update will resolve your problem. The usual support costs will apply to additional support questions and issues that do not qualify for the specific update in question.

Prerequisites
This update requires Microsoft .NET Framework Service Pack 1. For additional information about how to obtain the latest service pack for the .NET Framework, click the article number below to view the article in the Microsoft Knowledge Base:

318836 INFO: How to Obtain the Latest .NET Framework Service Pack

Download Information
To download the update for this problem, visit the following Microsoft Web site:

http://msdn.microsoft.com/netframework/downloads/updates/asphotfix.asp

Release Date: June 6, 2002

For additional information about how to download Microsoft Support files, click the following article number to view the article in the Microsoft Knowledge Base:

119591 How to Obtain Microsoft Support Files from Online Services

Microsoft scanned this file for viruses. Microsoft used the most current virus-detection software that was available on the date that the file was posted. The file is stored on security-enhanced servers that help to prevent any unauthorized changes to the file.

Installation Options
The following command-line command installs the update without any user intervention and does not force the computer to restart:

ndp10_qfem_q322296_sp.exe /Q

WARNING: Please see installation issues below and note that your computer is vulnerable until you restart it.

Installation Issues
For additional information about installation issues with this security bulletin, click the article number below to view the article in the Microsoft Knowledge Base:

324292 INFO: Installation Issues with Silent Install of Security Bulletin MS02-026

File Information
The following files are copied to the %WINDIR%\Microsoft.NET\Framework\v1.0.3705\ folder:   Version       File Name ---  1.0.3705.272  Aspnet_isapi.dll 1.0.3705.272 Aspnet_wp.exe 1.0.3705.272 Aspnet_regiis.exe --       Aspnet_perf.ini --       Aspnet_perf2.ini 1.0.3705.272 System.Web.dll The following files are copied to the %WINDIR%\Microsoft.NET\Framework\v1.0.3705\ASP.NETClientFiles\ folder:   Version  File Name ---  --       SmartNavIE5.js   --       SmartNav.js



STATUS
Microsoft has confirmed that this problem may cause a degree of security vulnerability in Microsoft ASP.NET.



MORE INFORMATION
For more information about this vulnerability, visit the following Microsoft Web site:

http://www.microsoft.com/technet/security/bulletin/MS02-026.asp

Additional query words: security_patch

Keywords: kbbug kbfix kbNetFrame100PreSP2fix kbQFE KbSECBulletin KbSECHack kbSecurity KbSECVulnerability KB322296

Technology: kbASPNet100 kbASPNetSearch kbASPsearch kbAudDeveloper kbNETFrameSearch

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