Security Only Update for .NET Framework 3.5 for Windows Server 2012 (KB4565577)

Summary

A remote code execution vulnerability exists in .NET Framework when the software fails to check the source markup of XML file input. An attacker who successfully exploited the vulnerability could run arbitrary code in the context of the process responsible for deserialization of the XML content. To exploit this vulnerability, an attacker could upload a specially crafted document to a server utilizing an affected product to process content. The security update addresses the vulnerability by correcting how .NET Framework validates the source markup of XML content.

This security update affects how .NET Framework's System.Data.DataTable and System.Data.DataSet types read XML-serialized data. Most .NET Framework applications will not experience any behavioral change after the update is installed. For more information on how the update affects .NET Framework, including examples of scenarios which may be affected, please see the DataTable and DataSet security guidance document at https://go.microsoft.com/fwlink/?linkid=2132227.

To learn more about the vulnerabilities, go to the following Common Vulnerabilities and Exposures (CVE).

• CVE-2020-1147

Known Issues

Symptoms:

After you apply this update, some applications experience a TypeInitializationException exception when they try to deserialize System.Data.DataSet or System.Data.DataTable instances from the XML within a SQL CLR stored procedure. The stack trace for this exception appears as follows:

System.TypeInitializationException: The type initializer for 'Scope' threw an exception. ---> System.IO.FileNotFoundException: Could not load file or assembly 'System.Drawing, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a' or one of its dependencies. The system cannot find the file specified.
     at System.Data.TypeLimiter.Scope.IsTypeUnconditionallyAllowed(Type type)
     at System.Data.TypeLimiter.Scope.IsAllowedType(Type type)
     at System.Data.TypeLimiter.EnsureTypeIsAllowed(Type type, TypeLimiter capturedLimiter)

Resolution:

Install the latest version of this update that was released on October 13th, 2020.

Additional information about this update

The following articles contain additional information about this update as it relates to individual product versions.

• 4566467 Description of the Security Only Update for .NET Framework 3.5, 4.5.2, 4.6, 4.6.1, 4.6.2, 4.7, 4.7.1, 4.7.2, 4.8 for Windows Server 2012 (KB4566467)

How to obtain and install the update

Before installing this update

Prerequisite:

To apply this update, you must have .NET Framework 3.5 installed.

Install this update

File information

File hash information

For all supported x64-based versions

Information about protection and security

• Protect yourself online: Windows Security support

• Learn how we guard against cyber threats: Microsoft Security