Microsoft Releases October 2021 Patch Tuesday Fixes

There are 3 Critical, 67 Important and a single Low fix in this October Patch Tuesday. Fixes include Microsoft Windows and Windows components, Microsoft Edge, Azure, Office and Office Components, SharePoint Server, Microsoft Windows DNS, and the Windows 11 has its first every security patch.

Year 2 Extended Support – Windows 7 and Windows Server 2008 (including R2) have received some updates this month, with one currently Weaponized.

1. Windows 7 – 19 Important vulnerabilities fixed
2. Windows 2008 R2 – 20 Important vulnerabilities fixed

Robert Brown, Head of Customer Success for Syxsense said, “This may be the first time ever that Microsoft released updates for four end user based operating systems (Windows 7, 8.1, 10 & now 11. Over the next couple of months, we could see an increase in the number of vulnerabilities fixed breaching 100 once again. Should that be the case, careful selection of the most important vulnerabilities to resolve will be extremely important.”

Top October 2021 Patches and Vulnerabilities

Based on the Vendor Severity and CVSS Score, we have made a few recommendations below. As usual, we recommend entering the CVE numbers below into your patch management solution and deploying as soon as possible. 

1. CVE-2021-40449: Win32k Elevation of Privilege Vulnerability

A local user can run a specially crafted program to trigger memory corruption and execute arbitrary code with elevated privileges. They can achieve this due to a boundary error within the Win32k driver in Microsoft Windows kernel.

This vulnerability was discovered by Kaspersky, therefore one may assume this may be used in the next ransomware attack if not resolved quickly.

Syxscore

• Vendor Severity: Important
• CVSS: 7.8
• Weaponized: Yes
• Public Aware: No
• Countermeasure: No

Syxscore Risk

• Attack Vector: Local
• Attack Complexity: Low
• Privileges: Low
• User Interaction: None
• Scope (Jump Point): No

2. CVE-2021-41335: Windows Kernel Elevation of Privilege Vulnerability

The vulnerability allows a local user to escalate privileges on the system because Windows does not properly impose security restrictions in Windows Kernel.

Syxscore

• Vendor Severity: Important
• CVSS: 7.8
• Weaponized: No
• Public Aware: Yes
• Countermeasure: No

Syxscore Risk

• Attack Vector: Local
• Attack Complexity: Low
• Privileges: None
• User Interaction: None
• Scope (Jump Point): No

3. CVE-2021-36970: Windows Print Spooler Spoofing Vulnerability

A remote attacker can spoof page content because the Windows Print Spooler incorrectly processes user supplied data. This vulnerability is more likely to be targeted by hackers because of the recent report of printing issues which are ongoing.

Syxscore

• Vendor Severity: Important
• CVSS: 8.8
• Weaponized: No
• Public Aware: No
• Countermeasure: No

Syxscore Risk

• Attack Vector: Network
• Attack Complexity: Low
• Privileges: None
• User Interaction: Required
• Scope (Jump Point): No

Syxsense Recommendations

Based on the vendor severity and CVSS Score, we have made a few recommendations below which you should prioritize this month. Please pay close attention to any of these which are publicly aware or weaponized.

 

CVE Reference	Description	Vendor Severity	CVSS Score	Countermeasure	Publicly Aware	Weaponised	Syxsense Recommended
CVE-2021-40449	Win32k Elevation of Privilege Vulnerability	Important	7.8	No	No	Yes	Yes
CVE-2021-41335	Windows Kernel Elevation of Privilege Vulnerability	Important	7.8	No	Yes	No	Yes
CVE-2021-40469	Windows DNS Server Remote Code Execution Vulnerability	Important	7.2	No	Yes	No	Yes
CVE-2021-41338	Windows AppContainer Firewall Rules Security Feature Bypass Vulnerability	Important	5.5	No	Yes	No	Yes
CVE-2021-38672	Windows Hyper-V Remote Code Execution Vulnerability	Critical	8	No	No	No	Yes
CVE-2021-40461	Windows Hyper-V Remote Code Execution Vulnerability	Critical	8	No	No	No	Yes
CVE-2021-40486	Microsoft Word Remote Code Execution Vulnerability	Critical	7.8	No	No	No	Yes
CVE-2021-26427	Microsoft Exchange Server Remote Code Execution Vulnerability	Important	9	No	No	No	Yes
CVE-2021-36970	Windows Print Spooler Spoofing Vulnerability	Important	8.8	No	No	No	Yes
CVE-2021-41344	Microsoft SharePoint Server Remote Code Execution Vulnerability	Important	8.1	No	No	No	Yes
CVE-2021-40487	Microsoft SharePoint Server Remote Code Execution Vulnerability	Important	8.1	No	No	No	Yes
CVE-2021-41348	Microsoft Exchange Server Elevation of Privilege Vulnerability	Important	8	No	No	No	Yes
CVE-2021-40464	Windows Nearby Sharing Elevation of Privilege Vulnerability	Important	8	No	No	No	Yes
CVE-2021-40470	DirectX Graphics Kernel Elevation of Privilege Vulnerability	Important	7.8	No	No	No	Yes
CVE-2021-40471	Microsoft Excel Remote Code Execution Vulnerability	Important	7.8	No	No	No	Yes
CVE-2021-40473	Microsoft Excel Remote Code Execution Vulnerability	Important	7.8	No	No	No	Yes
CVE-2021-40474	Microsoft Excel Remote Code Execution Vulnerability	Important	7.8	No	No	No	Yes
CVE-2021-40479	Microsoft Excel Remote Code Execution Vulnerability	Important	7.8	No	No	No	Yes
CVE-2021-40485	Microsoft Excel Remote Code Execution Vulnerability	Important	7.8	No	No	No	Yes
CVE-2021-40480	Microsoft Office Visio Remote Code Execution Vulnerability	Important	7.8	No	No	No	Yes
CVE-2021-41330	Microsoft Windows Media Foundation Remote Code Execution Vulnerability	Important	7.8	No	No	No	Yes
CVE-2021-40478	Storage Spaces Controller Elevation of Privilege Vulnerability	Important	7.8	No	No	No	Yes
CVE-2021-40488	Storage Spaces Controller Elevation of Privilege Vulnerability	Important	7.8	No	No	No	Yes
CVE-2021-40489	Storage Spaces Controller Elevation of Privilege Vulnerability	Important	7.8	No	No	No	Yes
CVE-2021-26441	Storage Spaces Controller Elevation of Privilege Vulnerability	Important	7.8	No	No	No	Yes
CVE-2021-41345	Storage Spaces Controller Elevation of Privilege Vulnerability	Important	7.8	No	No	No	Yes
CVE-2021-40450	Win32k Elevation of Privilege Vulnerability	Important	7.8	No	No	No	Yes
CVE-2021-41357	Win32k Elevation of Privilege Vulnerability	Important	7.8	No	No	No	Yes
CVE-2021-41347	Windows AppX Deployment Service Elevation of Privilege Vulnerability	Important	7.8	No	No	No	Yes
CVE-2021-40443	Windows Common Log File System Driver Elevation of Privilege Vulnerability	Important	7.8	No	No	No	Yes
CVE-2021-40466	Windows Common Log File System Driver Elevation of Privilege Vulnerability	Important	7.8	No	No	No	Yes
CVE-2021-40467	Windows Common Log File System Driver Elevation of Privilege Vulnerability	Important	7.8	No	No	No	Yes
CVE-2021-40477	Windows Event Tracing Elevation of Privilege Vulnerability	Important	7.8	No	No	No	Yes
CVE-2021-41340	Windows Graphics Component Remote Code Execution Vulnerability	Important	7.8	No	No	No	Yes
CVE-2021-41331	Windows Media Audio Decoder Remote Code Execution Vulnerability	Important	7.8	No	No	No	Yes
CVE-2021-40462	Windows Media Foundation Dolby Digital Atmos Decoders Remote Code Execution Vulnerability	Important	7.8	No	No	No	Yes
CVE-2021-40465	Windows Text Shaping Remote Code Execution Vulnerability	Important	7.8	No	No	No	Yes
CVE-2021-40463	Windows NAT Denial of Service Vulnerability	Important	7.7	No	No	No
CVE-2021-40484	Microsoft SharePoint Server Spoofing Vulnerability	Important	7.6	No	No	No
CVE-2021-34453	Microsoft Exchange Server Denial of Service Vulnerability	Important	7.5	No	No	No
CVE-2021-41352	SCOM Information Disclosure Vulnerability	Important	7.5	No	No	No
CVE-2021-40476	Windows AppContainer Elevation Of Privilege Vulnerability	Important	7.5	No	No	No
CVE-2021-36953	Windows TCP/IP Denial of Service Vulnerability	Important	7.5	No	No	No
CVE-2021-40457	Microsoft Dynamics 365 Customer Engagement Cross-Site Scripting Vulnerability	Important	7.4	No	No	No
CVE-2021-40481	Microsoft Office Visio Remote Code Execution Vulnerability	Important	7.1	No	No	No
CVE-2021-41334	Windows Desktop Bridge Elevation of Privilege Vulnerability	Important	7	No	No	No
CVE-2021-26442	Windows HTTP.sys Elevation of Privilege Vulnerability	Important	7	No	No	No
CVE-2021-41342	Windows MSHTML Platform Remote Code Execution Vulnerability	Important	6.8	No	No	No
CVE-2021-41350	Microsoft Exchange Server Spoofing Vulnerability	Important	6.5	No	No	No
CVE-2021-41332	Windows Print Spooler Information Disclosure Vulnerability	Important	6.5	No	No	No
CVE-2021-40460	Windows Remote Procedure Call Runtime Security Feature Bypass Vulnerability	Important	6.5	No	No	No
CVE-2021-41355	.NET Core and Visual Studio Information Disclosure Vulnerability	Important	5.7	No	No	No
CVE-2021-40472	Microsoft Excel Information Disclosure Vulnerability	Important	5.5	No	No	No
CVE-2021-40454	Rich Text Edit Control Information Disclosure Vulnerability	Important	5.5	No	No	No
CVE-2021-40468	Windows Bind Filter Driver Information Disclosure Vulnerability	Important	5.5	No	No	No
CVE-2021-40475	Windows Cloud Files Mini Filter Driver Information Disclosure Vulnerability	Important	5.5	No	No	No
CVE-2021-38663	Windows exFAT File System Information Disclosure Vulnerability	Important	5.5	No	No	No
CVE-2021-38662	Windows Fast FAT File System Driver Information Disclosure Vulnerability	Important	5.5	No	No	No
CVE-2021-41343	Windows Fast FAT File System Driver Information Disclosure Vulnerability	Important	5.5	No	No	No
CVE-2021-40455	Windows Installer Spoofing Vulnerability	Important	5.5	No	No	No
CVE-2021-41336	Windows Kernel Information Disclosure Vulnerability	Important	5.5	No	No	No
CVE-2021-41361	Active Directory Federation Server Spoofing Vulnerability	Important	5.4	No	No	No
CVE-2021-41353	Microsoft Dynamics 365 Sales Spoofing Vulnerability	Important	5.4	No	No	No
CVE-2021-41346	Console Window Host Security Feature Bypass Vulnerability	Important	5.3	No	No	No
CVE-2021-40482	Microsoft SharePoint Server Information Disclosure Vulnerability	Important	5.3	No	No	No
CVE-2021-40456	Windows AD FS Security Feature Bypass Vulnerability	Important	5.3	No	No	No
CVE-2021-41337	Active Directory Security Feature Bypass Vulnerability	Important	4.9	No	No	No
CVE-2021-41339	Microsoft DWM Core Library Elevation of Privilege Vulnerability	Important	4.7	No	No	No
CVE-2021-41363	Intune Management Extension Security Feature Bypass Vulnerability	Important	4.2	No	No	No
CVE-2021-41354	Microsoft Dynamics 365 (on-premises) Cross-site Scripting Vulnerability	Important	4.1	No	No	No
CVE-2021-40483	Microsoft SharePoint Server Spoofing Vulnerability	Low	7.6	No	No	No