Yes, it’s that time of the month again, and we have a lot to look at in terms of software release, as the December 2021 Patch Tuesday updates are now live.
The Redmond tech giant has released a number of 67 security fixes for software including seven critical issues and a zero-day flaw being actively exploited by malicious third parties.
Through this latest patch release, which is usually due on the second Tuesday of each month, Microsoft has fixed some important problems.
Among them are Remote Code Execution (RCE) vulnerabilities, privilege escalation security flaws, spoofing bugs, and denial-of-service issues.
Another notable event for this month’s rollout is the fact that Windows 10 version 2004 has reached end of support and will no longer receive any security updates.
Microsoft had a lot to work on for December as well
Some of the software targetted by Microsoft’s December security update include Office, PowerShell, the Chromium-based Edge browser, the Windows Kernel, Print Spooler, and Remote Desktop Client.
Some of the most severe vulnerabilities resolved in this update are a total of six zero-days, although only one is known to be actively exploited in the wild, as follows:
CVE | Title | Severity | CVSS | Public | Exploited | Type |
CVE-2021-43890 | Windows AppX Installer Spoofing Vulnerability | Important | 7.1 | Yes | Yes | Spoofing |
CVE-2021-43240 | NTFS Set Short Name Elevation of Privilege Vulnerability | Important | 7.8 | Yes | No | EoP |
CVE-2021-43893 | Windows Encrypting File System (EFS) Elevation of Privilege Vulnerability | Important | 7.5 | Yes | No | EoP |
CVE-2021-43883 | Windows Installer Elevation of Privilege Vulnerability | Important | 7.1 | Yes | No | EoP |
CVE-2021-43880 | Windows Mobile Device Management Elevation of Privilege Vulnerability | Important | 5.5 | Yes | No | EoP |
CVE-2021-41333 | Windows Print Spooler Elevation of Privilege Vulnerability | Important | 7.8 | Yes | No | EoP |
CVE-2021-43215 | iSNS Server Remote Code Execution Vulnerability | Critical | 9.8 | No | No | RCE |
CVE-2021-43899 | Microsoft 4K Wireless Display Adapter Remote Code Execution Vulnerability | Critical | 9.8 | No | No | RCE |
CVE-2021-42310 | Microsoft Defender for IoT Remote Code Execution Vulnerability | Critical | 8.1 | No | No | RCE |
CVE-2021-43905 | Microsoft Office app Remote Code Execution Vulnerability | Critical | 9.6 | No | No | RCE |
CVE-2021-43233 | Remote Desktop Client Remote Code Execution Vulnerability | Critical | 7 | No | No | RCE |
CVE-2021-43907 | Visual Studio Code WSL Extension Remote Code Execution Vulnerability | Critical | 9.8 | No | No | RCE |
CVE-2021-43217 | Windows Encrypting File System (EFS) Remote Code Execution Vulnerability | Critical | 8.1 | No | No | RCE |
CVE-2021-43877 | ASP.NET Core and Visual Studio Elevation of Privilege Vulnerability | Important | 7.8 | No | No | EoP |
CVE-2021-43225 | Bot Framework SDK Remote Code Execution Vulnerability | Important | 7.5 | No | No | RCE |
CVE-2021-43219 | DirectX Graphics Kernel File Denial of Service Vulnerability | Important | 7.4 | No | No | DoS |
CVE-2021-40452 | HEVC Video Extensions Remote Code Execution Vulnerability | Important | 7.8 | No | No | RCE |
CVE-2021-40453 | HEVC Video Extensions Remote Code Execution Vulnerability | Important | 7.8 | No | No | RCE |
CVE-2021-41360 | HEVC Video Extensions Remote Code Execution Vulnerability | Important | 7.8 | No | No | RCE |
CVE-2021-43892 | Microsoft BizTalk ESB Toolkit Spoofing Vulnerability | Important | 7.1 | No | No | Spoofing |
CVE-2021-42312 | Microsoft Defender for IOT Elevation of Privilege Vulnerability | Important | 7.8 | No | No | EoP |
CVE-2021-43888 | Microsoft Defender for IoT Information Disclosure Vulnerability | Important | 7.5 | No | No | Info |
CVE-2021-41365 | Microsoft Defender for IoT Remote Code Execution Vulnerability | Important | 8.8 | No | No | RCE |
CVE-2021-42311 | Microsoft Defender for IoT Remote Code Execution Vulnerability | Important | 8.8 | No | No | RCE |
CVE-2021-42313 | Microsoft Defender for IoT Remote Code Execution Vulnerability | Important | 8.8 | No | No | RCE |
CVE-2021-42314 | Microsoft Defender for IoT Remote Code Execution Vulnerability | Important | 8.8 | No | No | RCE |
CVE-2021-42315 | Microsoft Defender for IoT Remote Code Execution Vulnerability | Important | 8.8 | No | No | RCE |
CVE-2021-43882 | Microsoft Defender for IoT Remote Code Execution Vulnerability | Important | 9 | No | No | RCE |
CVE-2021-43889 | Microsoft Defender for IoT Remote Code Execution Vulnerability | Important | 7.2 | No | No | RCE |
CVE-2021-43256 | Microsoft Excel Remote Code Execution Vulnerability | Important | 7.8 | No | No | RCE |
CVE-2021-42293 | Microsoft Jet Red Database Engine and Access Connectivity Engine Elevation of Privilege Vulnerability | Important | 6.5 | No | No | EoP |
CVE-2021-43216 | Microsoft Local Security Authority Server (lsasrv) Information Disclosure Vulnerability | Important | 6.5 | No | No | Info |
CVE-2021-43222 | Microsoft Message Queuing Information Disclosure Vulnerability | Important | 7.5 | No | No | Info |
CVE-2021-43236 | Microsoft Message Queuing Information Disclosure Vulnerability | Important | 7.5 | No | No | Info |
CVE-2021-43875 | Microsoft Office Graphics Remote Code Execution Vulnerability | Important | 7.8 | No | No | RCE |
CVE-2021-43255 | Microsoft Office Trust Center Spoofing Vulnerability | Important | 5.5 | No | No | Spoofing |
CVE-2021-43896 | Microsoft PowerShell Spoofing Vulnerability | Important | 5.5 | No | No | Spoofing |
CVE-2021-42294 | Microsoft SharePoint Server Remote Code Execution Vulnerability | Important | 7.2 | No | No | RCE |
CVE-2021-42309 | Microsoft SharePoint Server Remote Code Execution Vulnerability | Important | 8.8 | No | No | RCE |
CVE-2021-42320 | Microsoft SharePoint Server Spoofing Vulnerability | Important | 8 | No | No | Spoofing |
CVE-2021-43242 | Microsoft SharePoint Server Spoofing Vulnerability | Important | 7.6 | No | No | Spoofing |
CVE-2021-43227 | Storage Spaces Controller Information Disclosure Vulnerability | Important | 5.5 | No | No | Info |
CVE-2021-43235 | Storage Spaces Controller Information Disclosure Vulnerability | Important | 5.5 | No | No | Info |
CVE-2021-43228 | SymCrypt Denial of Service Vulnerability | Important | 7.5 | No | No | DoS |
CVE-2021-42295 | Visual Basic for Applications Information Disclosure Vulnerability | Important | 5.5 | No | No | Info |
CVE-2021-43891 | Visual Studio Code Remote Code Execution Vulnerability | Important | 7.8 | No | No | RCE |
CVE-2021-43908 | Visual Studio Code Spoofing Vulnerability | Important | N/A | No | No | Spoofing |
CVE-2021-43243 | VP9 Video Extensions Information Disclosure Vulnerability | Important | 5.5 | No | No | Info |
CVE-2021-43214 | Web Media Extensions Remote Code Execution Vulnerability | Important | 7.8 | No | No | RCE |
CVE-2021-43207 | Windows Common Log File System Driver Elevation of Privilege Vulnerability | Important | 7.8 | No | No | EoP |
CVE-2021-43226 | Windows Common Log File System Driver Elevation of Privilege Vulnerability | Important | 7.8 | No | No | EoP |
CVE-2021-43224 | Windows Common Log File System Driver Information Disclosure Vulnerability | Important | 5.5 | No | No | Info |
CVE-2021-43248 | Windows Digital Media Receiver Elevation of Privilege Vulnerability | Important | 7.8 | No | No | EoP |
CVE-2021-43245 | Windows Digital TV Tuner Elevation of Privilege Vulnerability | Important | 7.8 | No | No | EoP |
CVE-2021-43232 | Windows Event Tracing Remote Code Execution Vulnerability | Important | 7.8 | No | No | RCE |
CVE-2021-43234 | Windows Fax Service Remote Code Execution Vulnerability | Important | 7.8 | No | No | RCE |
CVE-2021-43246 | Windows Hyper-V Denial of Service Vulnerability | Important | 5.6 | No | No | DoS |
CVE-2021-43244 | Windows Kernel Information Disclosure Vulnerability | Important | 6.5 | No | No | Info |
CVE-2021-40441 | Windows Media Center Elevation of Privilege Vulnerability | Important | 7.8 | No | No | EoP |
CVE-2021-43229 | Windows NTFS Elevation of Privilege Vulnerability | Important | 7.8 | No | No | EoP |
CVE-2021-43230 | Windows NTFS Elevation of Privilege Vulnerability | Important | 7.8 | No | No | EoP |
CVE-2021-43231 | Windows NTFS Elevation of Privilege Vulnerability | Important | 7.8 | No | No | EoP |
CVE-2021-43239 | Windows Recovery Environment Agent Elevation of Privilege Vulnerability | Important | 7.1 | No | No | EoP |
CVE-2021-43223 | Windows Remote Access Connection Manager Elevation of Privilege Vulnerability | Important | 7.8 | No | No | EoP |
CVE-2021-43238 | Windows Remote Access Elevation of Privilege Vulnerability | Important | 7.8 | No | No | EoP |
CVE-2021-43237 | Windows Setup Elevation of Privilege Vulnerability | Important | 7.8 | No | No | EoP |
CVE-2021-43247 | Windows TCP/IP Driver Elevation of Privilege Vulnerability | Important | 7.8 | No | No | EoP |
* CVE-2021-4052 | Chromium: CVE-2021-4052 Use after free in web apps | High | N/A | No | No | RCE |
* CVE-2021-4053 | Chromium: CVE-2021-4053 Use after free in UI | High | N/A | No | No | RCE |
* CVE-2021-4054 | Chromium: CVE-2021-4054 Incorrect security UI in autofill | High | N/A | No | No | RCE |
* CVE-2021-4055 | Chromium: CVE-2021-4055 Heap buffer overflow in extensions | High | N/A | No | No | RCE |
* CVE-2021-4056 | Chromium: CVE-2021-4056: Type Confusion in loader | High | N/A | No | No | RCE |
* CVE-2021-4057 | Chromium: CVE-2021-4057 Use after free in file API | High | N/A | No | No | RCE |
* CVE-2021-4058 | Chromium: CVE-2021-4058 Heap buffer overflow in ANGLE | High | N/A | No | No | RCE |
* CVE-2021-4059 | Chromium: CVE-2021-4059 Insufficient data validation in loader | High | N/A | No | No | RCE |
* CVE-2021-4061 | Chromium: CVE-2021-4061 Type Confusion in V8 | High | N/A | No | No | RCE |
* CVE-2021-4062 | Chromium: CVE-2021-4062 Heap buffer overflow in BFCache | High | N/A | No | No | RCE |
* CVE-2021-4063 | Chromium: CVE-2021-4063 Use after free in developer tools | High | N/A | No | No | RCE |
* CVE-2021-4064 | Chromium: CVE-2021-4064 Use after free in screen capture | High | N/A | No | No | RCE |
* CVE-2021-4065 | Chromium: CVE-2021-4065 Use after free in autofill | High | N/A | No | No | RCE |
* CVE-2021-4066 | Chromium: CVE-2021-4066 Integer underflow in ANGLE | High | N/A | No | No | RCE |
* CVE-2021-4067 | Chromium: CVE-2021-4067 Use after free in window manager | High | N/A | No | No | RCE |
* CVE-2021-4068 | Chromium: CVE-2021-4068 Insufficient validation of untrusted input in new tab page | Low | N/A | No | No | Spoofing |
A total of 887 CVE-assigned vulnerabilities have been patched by Microsoft this year, and while this figure may seem high, the team notes this is a 29% decrease from 2020 (not including Chromium-based Edge).
One of the most important victories here is that this patch fixes a bug in the AppX installer that affects Windows.
Redmond officials stated that they have seen the bug used in malware in the Emotet/Trickbot/Bazaloader family, and an attacker would need to craft a malicious attachment to be used in phishing campaigns.
It might actually seem that code execution would occur at the logged-on user level, so attackers would likely combine this with another bug to take control of a system.
Another bug, this time in the Internet Storage Name Service (iSNS) server, that could allow remote code execution if an attacker sends a specially crafted request to an affected server, has been squashed.
Just to refresh your memory, iSNS is a protocol that enables automated discovery and management of iSCSI devices on a TCP/IP storage network.
So, if you’re running a SAN in your enterprise, you either have an iSNS server or you configure each of the logical interfaces individually.
This bug is one of three CVSS 9.8 bugs fixed this month. If you have a SAN, prioritize testing and deploying this patch.
Don’t forget that Microsoft isn’t the only company that releases updates and fix patches around this time of the month, so make sure to also check out:
What are your thoughts on this month’s release? Share your opinion with us in the comments section below.
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