A zero-day and testing of key printing features will drive August Windows updates

Though a DNS-spoofing vulnerability in Windows has been rated as a zero-day, the focus for this month’s updates should be on testing key Windows features prior to deployment.

Though a DNS spoofing vulnerability in Windows (CVE-2020-1464) has been rated as a zero-day due to reports of exploitation in the wild, the focus for this month’s updates should be on testing key Windows features prior to deployment. Primarily, printing and back-up scenarios will require your attention. You will also need to work with multiple and potentially overlapping updates to Window and the .NET development platform and, in some cases, Windows Store updates to your application portfolio.

Given the number and nature of changes we have seen in the update testing cycle during the past month, we advise a “Patch Now” approach to Windows 10, but with an extended test cycle on printing and more attention to the Windows 8.x platforms. Key testing scenarios This section reflects some of our "update hotspot” analysis that covers both desktop and server platforms across multiple versions of Windows. Each application portfolio is unique and represents a distinct testing profile. For this August update cycle, we have identified the following areas where further testing may be warranted for your environment:

  • Test your printers, including virtual printers. And, make sure that you open at least one PDF file (successfully).

  • Test your backup RESTORE scenarios after installing the latest update and following a reboot.

  • UWP deployments may require additional testing. This August update addresses an issue in Universal Windows Platform (UWP) apps that allows single sign-on authentication when an app does not have the Enterprise Authentication capability. With the release of CVE-2020-1509, UWP applications might begin prompting the user for credentials.

  • Starting in July 2020, all Windows Updates will disable the RemoteFX vGPU feature because of a security vulnerability. For more information about the vulnerability, see CVE-2020-1036 and KB4570006. After you install this update, attempts to start virtual machines (VM) that have RemoteFX vGPU enabled will fail. You can learn more here.

Once you are done testing your applications, you may want to reboot twice due to the recent changes in the Secure Boot blacklist. 

Known issues Each month, Microsoft includes a list of known issues that relate to the operating system and platforms included in this update cycle. I have referenced a few key issues that relate to the latest builds from Microsoft, including:

  • After installing KB4550969 or later, when using Microsoft Edge Legacy, you might receive the error,”0x80704006. Hmmmm…can’t reach this page” when attempting to reach websites on non-standard ports. Microsoft advises to use the latest version of (Chromium) Edge

You can also find Microsoft’s summary of Known Issues for this release in a single page. Major revisions Two major revision for documentation reasons have been released for July by Microsoft:

  • CVE-2020-0794: A documentation update to affected platforms. No action required.

  • CVE-2020-1347: A documentation update to affected platforms. No action required.

Mitigations and workarounds For this August release of updates, Microsoft has published a small number of potential workarounds and mitigation strategies that apply to vulnerabilities (CVEs) addressed this month, including:

  • CVE-2020-1472: See How to manage the changes in Netlogon secure channel connections associated with CVE-2020-1472 for more details.

  • CVE-2020-1530, CVE-2020-1537 : The security updates for supported editions of Windows 8.1 and Windows Server 2012 R2 are not immediately available. The updates will be released as soon as possible, and when they are available, customers will be notified via a revision to this CVE information.