MS02-026: Unchecked buffer in ASP.NET worker process (Japanese)

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.

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.

To resolve this problem, obtain the latest service pack for the Microsoft .NET Framework 1.0. For additional information, click the following article number to view the article in the Microsoft Knowledge Base:

Security update information

A supported security update is now available from Microsoft, but it is only intended to correct the problem that this article describes. Apply it only to systems 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 security update may receive additional testing. If your computer is sufficiently at risk, we recommend that you apply this security update now.

To resolve this problem immediately, download the security update by following the instructions later in this article or contact Microsoft Product Support Services to obtain the security update. For a complete list of Microsoft Product Support Services phone numbers and information about support costs, visit the following Microsoft Web site: 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 security update requires Microsoft .NET Framework 1.0 Service Pack 1.

Download information

To download the security update for this problem, visit the following Microsoft Web site: 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: 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 security update without any user intervention and does not force the computer to restart: Warning Before you use this installation method, see the "Installation issues" section. Note that your computer is vulnerable until you restart it.

Installation issues

For additional information about installation issues with this security update, click the following article number to view the article in the Microsoft Knowledge Base:

File information

The following files are copied to the %WINDIR%\Microsoft.NET\Framework\v1.0.3705\ folder: The following files are copied to the %WINDIR%\Microsoft.NET\Framework\v1.0.3705\ASP.NETClientFiles\ folder:

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

This problem was corrected in the Microsoft .NET Framework 1.0 Service Pack 2.

For more information about this vulnerability, visit the following Microsoft Web site: The localized security updates for this vulnerability (MS02-026) have different Microsoft Knowledge Base (KB) numbers. The KB number and the corresponding language of the localized security updates appear in the following table. For additional information, click the following article number to view the article in the Microsoft Knowledge Base: