Description of the Security Only update for .NET Framework 3.5 for Windows 8.1, RT 8.1, and Server 2012 R2 (KB 4344178)

Summary

This security update resolves an information disclosure vulnerability in Microsoft .NET Framework that could allow an attacker to access information in multi-tenant environments. The vulnerability is caused when .NET Framework is used in high-load/high-density network connections in which content from one stream can blend into another stream.

To exploit the vulnerability, an attacker who can access one tenant in a high-load/high-density environment could potentially trigger multi-tenanted data exposure from one customer to another.

This security update addresses the vulnerability by correcting the way that .NET Framework handles high-load/high-density network connections.

To learn more about this vulnerability, see Microsoft Common Vulnerabilities and Exposures CVE-2018-8360.

Important

• All updates for Windows RT 8.1, Windows 8.1, and Windows Server 2012 R2 require update KB 2919355 to be installed. We recommend that you install update KB 2919355 on your Windows RT 8.1-based, Windows 8.1-based, or Windows Server 2012 R2-based computer so that you receive updates in the future.

• 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.

Additional information about this security update

For more information about this security update as it relates to Windows 8.1, Windows RT 8.1, and Windows Server 2012 R2, see the following article in the Microsoft Knowledge Base:

4345681 Security Only updates for .NET Framework 3.5, 4.5.2, 4.6, 4.6.1, 4.6.2, 4.7, 4.7.1, and 4.7.2 for Windows 8.1, RT 8.1 and Server 2012 R2 (KB 4345681)

How to obtain and install the update

File information

File hash

File attributes

The English (United States) version of this update installs files that have the attributes that are listed in the following tables. The dates and the times for these files are listed in Coordinated Universal Time (UTC). The dates and the times for these files on your local computer are displayed in your local time together with your current daylight saving time (DST) bias. Additionally, the dates and the times may change when you perform certain operations on the files.

For all supported x86-based systems

For all supported x64-based systems

How to obtain help and support for this security update

• Help for installing updates: Windows Update FAQ

• Security solutions for IT professionals: TechNet Security Support and Troubleshooting

• Help for protecting your Windows-based products and services from viruses and malware: Microsoft Secure

• Local support according to your country: International Support