Patch Tuesday – February 2021

Click the icon to Follow me:- twitterTelegramRedditDiscord
Patch Tuesday - February 2021

The second Patch Tuesday of 2021 is relatively light on the vulnerability count, with 64 CVEs being addressed across the majority of Microsoft’s product families. Despite that, there’s still plenty to discuss this month.

Vulnerability Breakdown by Software Family

Family Vulnerability Count
Windows 28
ESU 14
Microsoft Office 11
Browser 9
Developer Tools 8
Microsoft Dynamics 2
Exchange Server 2
Azure 2
System Center 2

Exploited and Publicly Disclosed Vulnerabilities

One zero-day was announced: CVE-2021-1732 is a privilege elevation vulnerability affecting the Win32k component of Windows 10 and Windows Server 2019, reported to be exploited in the wild. Four vulnerabilities have been previously disclosed: CVE-2021-1727, a privilege elevation vulnerability in Windows Installer, affecting all supported versions of Windows; CVE-2021-24098, which is a denial of service (DoS) affecting Windows 10 and Server 2019; CVE-2021-24106, an information disclosure vulnerability affecting DirectX in Windows 10 and Server 2019; and CVE-2021-26701, an RCE in .NET Core.

Vulnerabilities in Windows TCP/IP

Microsoft also disclosed a set of three serious vulnerabilities affecting the TCP/IP networking stack in all supported versions of Windows. Two of these (CVE-2021-24074 and CVE-2021-24094) carry a base CVSSv3 score of 9.8 and could allow Remote Code Execution (RCE). CVE-2021-24094 is specific to IPv6 link-local addresses, meaning it isn’t exploitable over the public internet. CVE-2021-24074, however, does not have this limitation. The third, CVE-2021-24086, is a DoS vulnerability that could allow an attacker to trigger a “blue screen of death” on any Windows system that is directly exposed to the internet, using only a small amount of network traffic. The RCE exploits are probably not a threat in the short term, due to the complexity of the vulnerabilities, but DoS attacks are expected to be seen much more quickly. Windows systems should be patched as soon as possible to protect against these.

In the event a patch cannot be applied immediately, such as on systems that cannot be rebooted, Microsoft has published mitigation guidance that will protect against exploitation of the TCP/IP vulnerabilities. Depending on the exposure of an asset, IPv4 Source Routing should be disabled via a Group Policy or a Netsh command, and IPv6 packet reassembly should be disabled via a separate Netsh command. IPv4 Source Routing requests and IPv6 fragments can also be blocked load balancers, firewalls, or other edge devices to mitigate these issues.

Zerologon Update

Back in August, 2020, Microsoft addressed a critical remote code vulnerability (CVE-2020-1472) affecting the Netlogon protocol (MS-NRPC), a.k.a. “Zerologon”. In October, Microsoft noted that attacks which exploit this weakness have been seen in the wild. On January 14, 2021, they reminded organizations that the February 2021 security update bundle will also be enabling “Domain Controller enforcement mode” by default to fully address this weakness. Any system that tries to make an insecure Netlogon connection will be denied access. Any business-critical process that relies on these insecure connections will cease to function. Rapid7 encourages all organizations to heed the detailed guidance before applying the latest updates to ensure continued business process continuity.

Adobe

Most important amongst the six security advisories published by Adobe today is APSB21-09, detailing 23 CVEs affecting Adobe Acrobat and Reader. Six of these are rated Critical and allow Arbitrary Code Execution, and one of which (CVE-2021-21017), has been seen exploited in the wild in attacks targeting Adobe Reader users on Windows.

Summary Tables

Azure Vulnerabilities

CVE Vulnerability Title Exploited Publicly Disclosed CVSSv3 Base Score FAQ?
CVE-2021-24109 Microsoft Azure Kubernetes Service Elevation of Privilege Vulnerability No No 6.8 Yes
CVE-2021-24087 Azure IoT CLI extension Elevation of Privilege Vulnerability No No 7 Yes

Browser Vulnerabilities

CVE Vulnerability Title Exploited Publicly Disclosed CVSSv3 Base Score FAQ?
CVE-2021-24100 Microsoft Edge for Android Information Disclosure Vulnerability No No 5 Yes
CVE-2021-24113 Microsoft Edge (Chromium-based) Security Feature Bypass Vulnerability No No 4.6 Yes
CVE-2021-21148 Chromium CVE-2021-21148: Heap buffer overflow in V8 N/A N/A nan Yes
CVE-2021-21147 Chromium CVE-2021-21147: Inappropriate implementation in Skia N/A N/A nan Yes
CVE-2021-21146 Chromium CVE-2021-21146: Use after free in Navigation N/A N/A nan Yes
CVE-2021-21145 Chromium CVE-2021-21145: Use after free in Fonts N/A N/A nan Yes
CVE-2021-21144 Chromium CVE-2021-21144: Heap buffer overflow in Tab Groups N/A N/A nan Yes
CVE-2021-21143 Chromium CVE-2021-21143: Heap buffer overflow in Extensions N/A N/A nan Yes
CVE-2021-21142 Chromium CVE-2021-21142: Use after free in Payments N/A N/A nan Yes

Developer Tools Vulnerabilities

CVE Vulnerability Title Exploited Publicly Disclosed CVSSv3 Base Score FAQ?
CVE-2021-26700 Visual Studio Code npm-script Extension Remote Code Execution Vulnerability No No 7.8 Yes
CVE-2021-1639 Visual Studio Code Remote Code Execution Vulnerability No No 7 No
CVE-2021-1733 Sysinternals PsExec Elevation of Privilege Vulnerability No Yes 7.8 Yes
CVE-2021-24105 Package Managers Configurations Remote Code Execution Vulnerability No No 8.4 Yes
CVE-2021-24111 .NET Framework Denial of Service Vulnerability No No 7.5 No
CVE-2021-1721 .NET Core and Visual Studio Denial of Service Vulnerability No Yes 6.5 No
CVE-2021-26701 .NET Core Remote Code Execution Vulnerability No Yes 8.1 Yes
CVE-2021-24112 .NET Core Remote Code Execution Vulnerability No No 8.1 Yes

ESU Windows Vulnerabilities

CVE Vulnerability Title Exploited Publicly Disclosed CVSSv3 Base Score FAQ?
CVE-2021-24080 Windows Trust Verification API Denial of Service Vulnerability No No 6.5 No
CVE-2021-24074 Windows TCP/IP Remote Code Execution Vulnerability No No 9.8 Yes
CVE-2021-24094 Windows TCP/IP Remote Code Execution Vulnerability No No 9.8 Yes
CVE-2021-24086 Windows TCP/IP Denial of Service Vulnerability No No 7.5 Yes
CVE-2021-1734 Windows Remote Procedure Call Information Disclosure Vulnerability No No 7.5 Yes
CVE-2021-25195 Windows PKU2U Elevation of Privilege Vulnerability No No 7.8 Yes
CVE-2021-24088 Windows Local Spooler Remote Code Execution Vulnerability No No 8.8 No
CVE-2021-1727 Windows Installer Elevation of Privilege Vulnerability No Yes 7.8 No
CVE-2021-24077 Windows Fax Service Remote Code Execution Vulnerability No No 9.8 Yes
CVE-2021-1722 Windows Fax Service Remote Code Execution Vulnerability No No 8.1 Yes
CVE-2021-24102 Windows Event Tracing Elevation of Privilege Vulnerability No No 7.8 No
CVE-2021-24103 Windows Event Tracing Elevation of Privilege Vulnerability No No 7.8 No
CVE-2021-24078 Windows DNS Server Remote Code Execution Vulnerability No No 9.8 Yes
CVE-2021-24083 Windows Address Book Remote Code Execution Vulnerability No No 7.8 No

Exchange Server Vulnerabilities

CVE Vulnerability Title Exploited Publicly Disclosed CVSSv3 Base Score FAQ?
CVE-2021-24085 Microsoft Exchange Server Spoofing Vulnerability No No 6.5 Yes
CVE-2021-1730 Microsoft Exchange Server Spoofing Vulnerability No No 5.4 Yes

Microsoft Dynamics Vulnerabilities

CVE Vulnerability Title Exploited Publicly Disclosed CVSSv3 Base Score FAQ?
CVE-2021-1724 Microsoft Dynamics Business Central Cross-site Scripting Vulnerability No No 6.1 No
CVE-2021-24101 Microsoft Dataverse Information Disclosure Vulnerability No No 6.5 Yes

Microsoft Office Vulnerabilities

CVE Vulnerability Title Exploited Publicly Disclosed CVSSv3 Base Score FAQ?
CVE-2021-24073 Skype for Business and Lync Spoofing Vulnerability No No 6.5 No
CVE-2021-24099 Skype for Business and Lync Denial of Service Vulnerability No No 6.5 No
CVE-2021-24114 Microsoft Teams iOS Information Disclosure Vulnerability No No 5.7 Yes
CVE-2021-1726 Microsoft SharePoint Spoofing Vulnerability No No 8 Yes
CVE-2021-24072 Microsoft SharePoint Server Remote Code Execution Vulnerability No No 8.8 No
CVE-2021-24066 Microsoft SharePoint Remote Code Execution Vulnerability No No 8.8 Yes
CVE-2021-24071 Microsoft SharePoint Information Disclosure Vulnerability No No 5.3 Yes
CVE-2021-24067 Microsoft Excel Remote Code Execution Vulnerability No No 7.8 Yes
CVE-2021-24068 Microsoft Excel Remote Code Execution Vulnerability No No 7.8 Yes
CVE-2021-24069 Microsoft Excel Remote Code Execution Vulnerability No No 7.8 Yes
CVE-2021-24070 Microsoft Excel Remote Code Execution Vulnerability No No 7.8 Yes

System Center Vulnerabilities

CVE Vulnerability Title Exploited Publicly Disclosed CVSSv3 Base Score FAQ?
CVE-2021-1728 System Center Operations Manager Elevation of Privilege Vulnerability No No 8.8 Yes
CVE-2021-24092 Microsoft Defender Elevation of Privilege Vulnerability No No 7.8 Yes

Windows Vulnerabilities

CVE Vulnerability Title Exploited Publicly Disclosed CVSSv3 Base Score FAQ?
CVE-2021-1732 Windows Win32k Elevation of Privilege Vulnerability Yes No 7.8 No
CVE-2021-1698 Windows Win32k Elevation of Privilege Vulnerability No No 7.8 No
CVE-2021-24075 Windows Network File System Denial of Service Vulnerability No No 6.8 No
CVE-2021-24084 Windows Mobile Device Management Information Disclosure Vulnerability No No 5.5 Yes
CVE-2021-24096 Windows Kernel Elevation of Privilege Vulnerability No No 7.8 No
CVE-2021-24093 Windows Graphics Component Remote Code Execution Vulnerability No No 8.8 Yes
CVE-2021-24106 Windows DirectX Information Disclosure Vulnerability No Yes 5.5 Yes
CVE-2021-24098 Windows Console Driver Denial of Service Vulnerability No Yes 5.5 Yes
CVE-2021-24091 Windows Camera Codec Pack Remote Code Execution Vulnerability No No 7.8 No
CVE-2021-24079 Windows Backup Engine Information Disclosure Vulnerability No No 5.5 Yes
CVE-2021-1731 PFX Encryption Security Feature Bypass Vulnerability No No 5.5 Yes
CVE-2021-24082 Microsoft.PowerShell.Utility Module WDAC Security Feature Bypass Vulnerability No No 4.3 No
CVE-2021-24076 Microsoft Windows VMSwitch Information Disclosure Vulnerability No No 5.5 Yes
CVE-2021-24081 Microsoft Windows Codecs Library Remote Code Execution Vulnerability No No 7.8 No

Summary Charts

Patch Tuesday - February 2021
Patch Tuesday - February 2021
Patch Tuesday - February 2021
Patch Tuesday - February 2021

Note: Chart data is reflective of data presented by Microsoft’s CVRF at the time of writing.

If you like the site, please consider joining the telegram channel or supporting us on Patreon using the button below.

Discord

Original Source