Patch Office and Windows now to resolve two zero-days

Microsoft has resolved 80 new CVEs this month along with 4 earlier CVEs, bringing the variety of safety points addressed on this month’s Patch Tuesday launch to 84. 

Sadly, we’ve two zero-day flaws in Outlook (CVE-2023-23397) and Home windows (CVE-2023-24880) that require a “Patch Now” launch requirement for each Home windows and Microsoft Workplace updates. Because it was final month, there have been no additional updates for Microsoft Alternate Server or Adobe Reader. This month the crew at Utility Readiness has offered a useful infographic that outlines the dangers related to every of the updates for this cycle.

Recognized points

Every month, Microsoft features a listing of recognized points that relate to the working system and platforms included within the replace cycle.

  • KB5022842: After putting in KB5022842 on Home windows Server 2022 with Safe Boot enabled and rebooting twice, the VMware VM did not boot utilizing the brand new bootmgr. This situation remains to be into account by Microsoft. After putting in this replace, WPF apps might have a change in conduct.
  • After putting in this month’s Home windows replace on visitor digital machines (VMs) working Home windows Server 2022 on some variations of VMware ESXi, Home windows Server 2022 may not begin.

Microsoft remains to be engaged on a community efficiency situation with Home windows 11 22H2. Massive (multi-gigabyte) community file transfers (and doubtlessly equally giant native transfers) are affected. This situation ought to primarily have an effect on IT directors.

Main revisions

Microsoft printed 4 main revisions this month overlaying:

  • VE-2023-2156: Microsoft SQL Server Integration Service (VS extension) Distant Code Execution Vulnerability.
  • CVE-2022-41099: Title: BitLocker Safety Characteristic Bypass Vulnerability.
  • CVE-2023-21716: Microsoft Phrase Distant Code Execution Vulnerability.
  • CVE-2023-21808 .NET and Visible Studio Distant Code Execution Vulnerability.

All of those revisions have been because of documentation and expanded affected software program updates. No additional motion is required.

Mitigations and workarounds

Microsoft printed the next vulnerability associated mitigations for this month’s launch:

  • CVE-2023-23392: HTTP Protocol Stack Distant Code Execution Vulnerability. A prerequisite for a Home windows 2022 server to be susceptible to this safety situation is that the community binding has HTTP/3 enabled and the server makes use of buffered I/O. Enabling HTTP/3 is mentioned right here: Enabling HTTP/3 help on Home windows Server 2022.
  • CVE-2023-23397: Microsoft Outlook Elevation of Privilege Vulnerability. Microsoft has printed two mitigations for this severe safety situation:
  1. Add customers to the Protected Customers Safety Group, which prevents the usage of NTLM as an authentication mechanism.
  2. Block TCP 445/SMB outbound out of your community by utilizing a fringe firewall, an area firewall, and through your VPN settings.

Testing steering 

Every month, the crew at Readiness analyzes the Patch Tuesday updates and offers detailed, actionable testing steering; that steering is predicated on assessing a big software portfolio and an in depth evaluation of the Microsoft patches and their potential influence on the Home windows platforms and software installations.

Given the big variety of modifications included this month, I’ve damaged down the testing situations into high-risk and standard-risk teams.

Excessive threat

Microsoft printed a number of excessive threat modifications within the March replace. Whereas they might not result in performance modifications, the testing profile for every replace ought to be necessary:

  • Microsoft has up to date how DCOM responds to distant requests as a part of the current hardening effort. This course of has been below means since June 2021 (Section 1), with an replace in June 2022 (Section 2) and now this month with all modifications  carried out as necessary. DCOM is a core Home windows part used for speaking between providers or processes. Microsoft has suggested that this (and full deployment of previous suggestions) will trigger application-level compatibility points. The corporate has supplied some help on what’s altering and how one can mitigate any compatibility points on account of these current necessary settings.
  • A significant change to the core system file Win32kfull.sys has been included this month as two features (DrvPlgBlt and nf-wingdi-plgblt) have been up to date. Microsoft has suggested there aren’t any purposeful modifications to those features. Testing purposes that rely on these features will probably be important earlier than a full deployment of this month’s updates.

These situations require important application-level testing earlier than basic deployment.

  • Bluetooth: Strive including and eradicating new Bluetooth units. Stressing Bluetooth community units could be extremely suggested.
  • Home windows Community stack (TCPIP.SYS): Primary internet browsing, “regular” file transfers and video streaming ought to be adequate to check the modifications to the Home windows networking stack.
  • Hyper-V: Strive testing each Gen1 and Gen2 digital machines (VM’s). Each forms of machines ought to begin, cease, shut down, pause, and resume efficiently.

Along with these modifications, Microsoft up to date a key reminiscence operate (D3DKMTCreateDCFromMemory) that impacts two key system-level Home windows drivers (win32kbase.sys and win32kfull.sys). Sadly, in previous updates to those drivers, some customers have generated BSOD SYSTEM_SERVICE_EXCEPTION errors. Microsoft has posted data on how one can handle these points. Hopefully you do not have to resolve these sorts of points this month.

Home windows lifecycle replace

This part accommodates vital modifications to servicing (and most safety updates) to Home windows desktop and server platforms over the following few months:

  • Home windows 10 Enterprise (and Schooling), Model 20H2 and Home windows 10 IoT Enterprise, and Home windows Model 20H2 will attain an finish of servicing date on Might 9, 2023.

Every month, we break down the replace cycle into product households (as outlined by Microsoft) with the next fundamental groupings:

  • Browsers (Microsoft IE and Edge).
  • Microsoft Home windows (each desktop and server).
  • Microsoft Workplace.
  • Microsoft Alternate Server.
  • Microsoft Growth platforms (ASP.NET Core, .NET Core and Chakra Core).
  • Adobe (retired???, perhaps subsequent 12 months).


There have been 22 updates for March (none rated essential), with 21 included within the Google launch channel and one (CVE-2023-24892) from Microsoft. All these updates are easy-to-deploy updates with marginal to low deployment threat. Yow will discover Microsoft’s model of these launch notes right here and the Google Desktop channel launch notes right here. Add these updates to your commonplace patch launch schedule.

Home windows

Microsoft launched 10 essential updates and 48 patches rated as vital to the Home windows platform that cowl the next key elements:

  • Microsoft Printer Postscript Drivers.
  • Home windows Bluetooth Service.
  • Home windows Win32K and Core Graphics elements (GDI).
  • Home windows HTTP Protocol Stack and PPPoE.

Apart from the current change to DCOM authentication (see DCOM hardening) most of this month’s updates have a really low threat profile. We’ve a minor replace to a printing subsystem (Postscript 6) and different tweaks to community dealing with, storage, and graphics elements. Sadly, we’ve an actual zero-day situation with Home windows (CVE-2023-24880) SmartScreen (aka Home windows Defender) with reviews of each exploitation and a public disclosure. Consequently, add these Home windows updates to your “Patch Now” launch schedule.

Microsoft Workplace

Microsoft launched 11 updates to the Microsoft Workplace platform with one rated as (tremendous) essential and the remaining updates rated vital and affecting simply Excel and SharePoint. Sadly, the Microsoft Outlook replace (CVE-2023-23397) should be patched instantly. I’ve included suggestions supplied by Microsoft in our mitigations part above which embrace including customers to the next safety group and blocking ports 445/SMB in your community. Given the low threat of breaking different apps and the convenience of deployment of this patch, I’ve one other concept: add these Workplace updates to your “Patch Now” launch schedule.

Microsoft Alternate Server

No Microsoft Alternate updates required this month. That mentioned, there’s a significantly worrying situation with Microsoft Outlook (CVE-2023-23397) that will probably be sufficient for any mail administrator to deal with this month.

Microsoft improvement platforms

This can be a very mild patch cycle for Microsoft improvement platforms with simply 4 updates to Visible Studio (GitHub extensions) this month. All these updates are rated as vital by Microsoft and have a really low deployment threat profile. Add these updates to your commonplace developer launch schedule. 

Adobe Reader (nonetheless right here, however simply not this month)

We could also be seeing a development right here as Adobe has not launched any updates for Adobe Reader. It is usually attention-grabbing that that is the primary month in 9 that Microsoft has not launched any essential updates to its XPS, PDF or printing system. So, no necessary printer testing is required.

Copyright © 2023 IDG Communications, Inc.