Security and Quality Rollup for .NET Framework 2.0, 3.0, 4.5.2, 4.6 for Windows Server 2008 SP2 (KB4556402)

**Applies to:**Microsoft .NET Framework 2.0 Microsoft .NET Framework 3.0 Microsoft .NET Framework 4.5.2 Microsoft .NET Framework 4.6

IMPORTANTVerify thatyou have installed the required updates listed in the How to get this update section before installing this update.

IMPORTANT WSUS scan cab files will continue to be available for Windows Server 2008 SP2. If you have a subset of devices running this operating system without ESU, they might show as non-compliant in your patch management and compliance toolsets.

IMPORTANT Customers who have purchased the Extended Security Update (ESU) for on-premises versions of this OS must follow the procedures in KB4522133 to continue receiving security updates after extended support ends on January 14, 2020. For more information on ESU and which editions are supported, see KB4497181.

IMPORTANT Starting in August, 2019, updates to .NET Framework 4.6 and above, for Windows Server 2008 SP2 require SHA-2 Code signing support. Please make sure that you have all the latest Windows Updates before applying this update to avoid installation issues. For more detailed information about SHA-2 code signing support updates, please see KB 4474419.

IMPORTANT All updates for .NET Framework 4.7.2, 4.7.1, 4.7, 4.6.2, 4.6.1, and 4.6 require that the d3dcompiler_47.dll update is installed. We recommend that you install the included d3dcompiler_47.dll update before you apply this update. For more information about the d3dcompiler_47.dll, see KB 4019990.

IMPORTANT If you install a language pack after you install this update, you must reinstall this update. Therefore, we recommend that you install any language packs that you need before you install this update. For more information, see Add language packs to Windows.

Summary

An elevation of privilege vulnerability exists in .NET Framework which could allow an attacker to elevate their privilege level. To exploit the vulnerability, an attacker would first have to access the local machine, and then run a malicious program. The update addresses the vulnerability by correcting how .NET Framework activates COM objects. To learn more about the vulnerabilities, go to the following Common Vulnerabilities and Exposures (CVE).

• CVE-2020-1066
  A remote code execution vulnerability exists in .NET Framework software when the software fails to check the source markup of a file. An attacker who successfully exploited the vulnerability could run arbitrary code in the context of the current user. If the current user is logged on with administrative user rights, an attacker could take control of the affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights. Users whose accounts are configured to have fewer user rights on the system could be less impacted than users who operate with administrative user rights. Exploitation of the vulnerability requires that a user open a specially crafted file with an affected version of .NET Framework. In an email attack scenario, an attacker could exploit the vulnerability by sending the specially crafted file to the user and convincing the user to open the file. The security update addresses the vulnerability by correcting how .NET Framework checks the source markup of a file. To learn more about the vulnerabilities, go to the following Common Vulnerabilities and Exposures (CVE).
• CVE-2020-0605
  A denial of service vulnerability exists when .NET Framework improperly handles web requests. An attacker who successfully exploited this vulnerability could cause a denial of service against a .NET Framework web application. The vulnerability can be exploited remotely, without authentication. A remote unauthenticated attacker could exploit this vulnerability by issuing specially crafted requests to the .NET Framework application. The update addresses the vulnerability by correcting how the .NET Framework web application handles web requests. To learn more about the vulnerabilities, go to the following Common Vulnerabilities and Exposures (CVE).
• CVE-2020-1108

Known issues in some parts of this update

Symptom| This update does not install, and it returns either or both of the following error messages:

• -2146762495
• A required certificate is not within its validity period when verifying against the current system clock or the timestamp in the signed file.
  —|—
  Workaround| For details see the article for the .NET Framework individual product version for detailed instructions.

Additional information about this update

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

• 4552939 Description of the Security and Quality Rollup for .NET Framework 2.0, 3.0 for Windows Server 2008 SP2 (KB4552939)
• 4552920 Description of the Security and Quality Rollup for .NET Framework 4.5.2 for Windows 7 SP1 and Windows Server 2008 R2 SP1 and Windows Server 2008 SP2 (KB4552920)
• 4552919 Description of the Security and Quality Rollup for .NET Framework 4.6 for Windows 7 SP1 and Windows Server 2008 R2 SP1 and Windows Server 2008 SP2 (KB4552919)

Information about protection and security

• Protect yourself online: Windows Security support
• Learn how we guard against cyber threats: Microsoft Security