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

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.

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 following article number to view the article in the Microsoft Knowledge Base:

Download Information

For your convenience, this update is also available individually. To download the individual 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 update without any user intervention and does not force the computer to restart: Warning 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 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 first corrected in Microsoft .NET Framework Service Pack 2 (SP2).

For more information about this vulnerability, visit the following Microsoft Web site: The localized patches for this vulnerability (MS02-026) have different Microsoft Knowledge Base (KB) numbers. The KB number and the corresponding language for each localized patch appear in the following table.