Microsoft February 2021 Patch Tuesday fixes 56 bugs, including an actively exploited Windows zero

Visual Studio Code Remote Code Execution Vulnerability

Windows TCP/IP Remote Code Execution Vulnerability

.NET Core Remote Code Execution Vulnerability

Microsoft Dynamics Business Central Cross-site Scripting Vulnerability

System Center Operations Manager Elevation of Privilege Vulnerability

Microsoft Exchange Server Spoofing Vulnerability

CVE-2021-1732 is a local elevation-of-privilege vulnerability (CWE-787, out-of-bounds write) in Microsoft's Win32k kernel driver, publicly characterized as an "offset confusion" in the Win32k ConsoleControl routine. It is triggered locally: a process with only low privileges can invoke the vulnerable Win32k functionality without any user interaction, causing a user-supplied offset/pointer to be mishandled in kernel mode and memory to be written out of bounds. An attacker who successfully exploits the flaw can execute code in the kernel and elevate to SYSTEM, gaining full control of the host — which makes it a valuable second-stage link in malware and ransomware chains. Any system running the affected Windows 10 releases (1803, 1809, 1909, 2004, 20H2) or Windows Server 2019/1909/2004/20H2 is exposed, though exploitation requires the attacker to already run code locally on the target. The flaw was fixed in Microsoft's February 2021 Patch Tuesday updates, was added to CISA's KEV catalog on 2021-11-03 with known ransomware use, and carries a very high EPSS score (78.4%, 100th percentile), indicating sustained exploitation pressure.

Do: Apply Microsoft's February 2021 (or later) Windows cumulative security updates to all affected Windows 10 and Windows Server systems, per vendor instructions — CISA's KEV listing requires federal agencies to patch. Prioritize hosts exposed to untrusted local users or already compromised by malware (e.g., ransomware or Raspberry Robin activity, which has used chained Windows LPEs), and hunt on unpatched hosts for signs of post-exploitation privilege escalation to SYSTEM.

Sysinternals PsExec Elevation of Privilege Vulnerability

Microsoft SharePoint Remote Code Execution Vulnerability

Microsoft Excel Remote Code Execution Vulnerability

Microsoft Excel Remote Code Execution Vulnerability

Skype for Business and Lync Denial of Service Vulnerability

Windows DNS Server Remote Code Execution Vulnerability

Azure IoT CLI extension Elevation of Privilege Vulnerability

Microsoft Defender Elevation of Privilege Vulnerability

Microsoft Edge for Android Information Disclosure Vulnerability

Microsoft Dataverse Information Disclosure Vulnerability

Depending on configuration of various package managers it is possible for an attacker to insert a malicious package into a package manager's repository which can be retrieved and used during development, build, and release processes. This insertion could lead to remote code execution. We believe this vulnerability affects multiple package managers across multiple languages, including but not limited to: Python/pip, .NET/NuGet, Java/Maven, JavaScript/npm. Attack scenarios An attacker could take advantage of this ecosystem-wide issue to cause harm in a variety of ways. The original attack scenarios were discovered by Alex Birsan and are detailed in their whitepaper, Dependency Confusion: How I Hacked Into Apple, Microsoft and Dozens of Other Companies . With basic knowledge of the target ecosystems, an attacker could create an empty shell for a package and insert malicious code in the install scripts, give it a high version, and publish it to the public repository. Vulnerable victim machines will download the higher version of the package between the public and private repositories and attempt to install it. Due to code incompatibility it will probably error out upon import or upon compilation, making it easier to detect; however the attacker would have gained code execution by that point. An advanced attacker with some inside knowledge of the target could take a copy of a working package, insert the malicious code (in the package itself or in the install), and then publish it to a public repository. The package will likely install and import correctly, granting the attacker an initial foothold and persistence. These two methods could affect target organizations at any of these various levels: Developer machines An entire team if the configuration to import the malicious package is uploaded to a code repository Continuous integration pipelines if they pull the malicious packages during the build, test, and/or deploy stages Customers, download servers, production services if the malicious code has not been detected This remote code execution vulnerability can only be addressed by reconfiguring installation tools and workflows, and not by correcting anything in the package repositories themselves. See the FAQ section of this CVE for configuration guidance.

Microsoft Azure Kubernetes Service Elevation of Privilege Vulnerability

.NET Framework Denial of Service Vulnerability

Microsoft Teams iOS Information Disclosure Vulnerability

Visual Studio Code npm-script Extension Remote Code Execution Vulnerability