Microsoft has released today its monthly batch of security updates, known as Patch Tuesday. This month, the OS maker has fixed 56 security vulnerabilities, including a Windows bug that was being exploited in the wild before today’s patches.
Tracked as CVE-2021-1732, the Windows zero-day is an elevation of privelege bug in Win32k, a core component of the Windows operating system.
The bug was exploited after attackers gained access to a Windows system in order to obtain SYSTEM-level access.
Details about the attacks where this bug was used were not revealed. Microsoft credited three security researchers from Chinese security firm DBAPPSecurity with discovering the attacks where this zero-day was employed.
Many bug details went public
Besides the zero-day, this month’s Patch Tuesday also stands out because of the high number of vulnerabilities whose details were made public even before patches were available.
In total, six Microsoft product bugs had their details posted online before today’s patches. This included:
CVE-2021-1721 – .NET Core and Visual Studio Denial of Service VulnerabilityCVE-2021-1733 – Sysinternals PsExec Elevation of Privilege VulnerabilityCVE-2021-26701 – .NET Core Remote Code Execution VulnerabilityCVE-2021-1727 – Windows Installer Elevation of Privilege VulnerabilityCVE-2021-24098 – Windows Console Driver Denial of Service VulnerabilityCVE-2021-24106 – Windows DirectX Information Disclosure Vulnerability
The good news is that none of these bugs were exploited by attackers, despite their details being posted online.
Warning about TCP/IP bugs
But that’s not all. This month, Microsoft has also released fixes for three vulnerabilities in the Windows TCP/IP stack, which allows the operating system to connect to the internet.
Two of these bugs (CVE-2021-24074, CVE-2021-24094) apply fixes for remote code execution vulnerabilities that could allow attackers to take over Windows systems remotely.
A third bug (CVE-2021-24086) could be used to crash Windows devices.
“The two RCE vulnerabilities are complex which make it difficult to create functional exploits, so they are not likely [to be exploited] in the short term,” Microsoft said in a blog post specifically published to warn about these three issues.
“We believe attackers will be able to create DoS exploits much more quickly and expect all three issues might be exploited with a DoS attack shortly after release,” the company added. “Thus, we recommend customers move quickly to apply Windows security updates this month.”
Of all Windows systems, Windows Server instances are the ones most likely to be susceptible to attacks, as many are used to host web servers or cloud infrastructure and are almost certainly connected to the internet at all times and exposed to attacks.
“It is essential that customers apply Windows updates to address these vulnerabilities as soon as possible,” Microsoft said.
If patches can’t be applied right away, various workarounds can be deployed, details in each vulnerability’s advisory.
Below are additional details about today’s Microsoft Patch Tuesday and security updates released by other tech companies:
Microsoft’s official Security Update Guide portal lists all security updates in a filterable table.ZDNet has published this file listing all this month’s security advisories on one single page.Adobe’s security updates are detailed here.SAP security updates are available here.Intel security updates are available here.VMWare security updates are available here.Chrome 88 security updates are detailed here.Android security updates are available here.TagCVE IDCVE Title .NET Core CVE-2021-26701 .NET Core Remote Code Execution Vulnerability .NET Core CVE-2021-24112 .NET Core Remote Code Execution Vulnerability .NET Core & Visual Studio CVE-2021-1721 .NET Core and Visual Studio Denial of Service Vulnerability .NET Framework CVE-2021-24111 .NET Framework Denial of Service Vulnerability Azure IoT CVE-2021-24087 Azure IoT CLI extension Elevation of Privilege Vulnerability Developer Tools CVE-2021-24105 Package Managers Configurations Remote Code Execution Vulnerability Microsoft Azure Kubernetes Service CVE-2021-24109 Microsoft Azure Kubernetes Service Elevation of Privilege Vulnerability Microsoft Dynamics CVE-2021-24101 Microsoft Dataverse Information Disclosure Vulnerability Microsoft Dynamics CVE-2021-1724 Microsoft Dynamics Business Central Cross-site Scripting Vulnerability Microsoft Edge for Android CVE-2021-24100 Microsoft Edge for Android Information Disclosure Vulnerability Microsoft Exchange Server CVE-2021-24085 Microsoft Exchange Server Spoofing Vulnerability Microsoft Exchange Server CVE-2021-1730 Microsoft Exchange Server Spoofing Vulnerability Microsoft Graphics Component CVE-2021-24093 Windows Graphics Component Remote Code Execution Vulnerability Microsoft Office Excel CVE-2021-24067 Microsoft Excel Remote Code Execution Vulnerability Microsoft Office Excel CVE-2021-24068 Microsoft Excel Remote Code Execution Vulnerability Microsoft Office Excel CVE-2021-24069 Microsoft Excel Remote Code Execution Vulnerability Microsoft Office Excel CVE-2021-24070 Microsoft Excel Remote Code Execution Vulnerability Microsoft Office SharePoint CVE-2021-24071 Microsoft SharePoint Information Disclosure Vulnerability Microsoft Office SharePoint CVE-2021-1726 Microsoft SharePoint Spoofing Vulnerability Microsoft Office SharePoint CVE-2021-24066 Microsoft SharePoint Remote Code Execution Vulnerability Microsoft Office SharePoint CVE-2021-24072 Microsoft SharePoint Server Remote Code Execution Vulnerability Microsoft Teams CVE-2021-24114 Microsoft Teams iOS Information Disclosure Vulnerability Microsoft Windows Codecs Library CVE-2021-24081 Microsoft Windows Codecs Library Remote Code Execution Vulnerability Microsoft Windows Codecs Library CVE-2021-24091 Windows Camera Codec Pack Remote Code Execution Vulnerability Role: DNS Server CVE-2021-24078 Windows DNS Server Remote Code Execution Vulnerability Role: Hyper-V CVE-2021-24076 Microsoft Windows VMSwitch Information Disclosure Vulnerability Role: Windows Fax Service CVE-2021-24077 Windows Fax Service Remote Code Execution Vulnerability Role: Windows Fax Service CVE-2021-1722 Windows Fax Service Remote Code Execution Vulnerability Skype for Business CVE-2021-24073 Skype for Business and Lync Spoofing Vulnerability Skype for Business CVE-2021-24099 Skype for Business and Lync Denial of Service Vulnerability SysInternals CVE-2021-1733 Sysinternals PsExec Elevation of Privilege Vulnerability System Center CVE-2021-1728 System Center Operations Manager Elevation of Privilege Vulnerability Visual Studio CVE-2021-1639 Visual Studio Code Remote Code Execution Vulnerability Visual Studio Code CVE-2021-26700 Visual Studio Code npm-script Extension Remote Code Execution Vulnerability Windows Address Book CVE-2021-24083 Windows Address Book Remote Code Execution Vulnerability Windows Backup Engine CVE-2021-24079 Windows Backup Engine Information Disclosure Vulnerability Windows Console Driver CVE-2021-24098 Windows Console Driver Denial of Service Vulnerability Windows Defender CVE-2021-24092 Microsoft Defender Elevation of Privilege Vulnerability Windows DirectX CVE-2021-24106 Windows DirectX Information Disclosure Vulnerability Windows Event Tracing CVE-2021-24102 Windows Event Tracing Elevation of Privilege Vulnerability Windows Event Tracing CVE-2021-24103 Windows Event Tracing Elevation of Privilege Vulnerability Windows Installer CVE-2021-1727 Windows Installer Elevation of Privilege Vulnerability Windows Kernel CVE-2021-24096 Windows Kernel Elevation of Privilege Vulnerability Windows Kernel CVE-2021-1732 Windows Win32k Elevation of Privilege Vulnerability Windows Kernel CVE-2021-1698 Windows Win32k Elevation of Privilege Vulnerability Windows Mobile Device Management CVE-2021-24084 Windows Mobile Device Management Information Disclosure Vulnerability Windows Network File System CVE-2021-24075 Windows Network File System Denial of Service Vulnerability Windows PFX Encryption CVE-2021-1731 PFX Encryption Security Feature Bypass Vulnerability Windows PKU2U CVE-2021-25195 Windows PKU2U Elevation of Privilege Vulnerability Windows PowerShell CVE-2021-24082 Microsoft.PowerShell.Utility Module WDAC Security Feature Bypass Vulnerability Windows Print Spooler Components CVE-2021-24088 Windows Local Spooler Remote Code Execution Vulnerability Windows Remote Procedure Call CVE-2021-1734 Windows Remote Procedure Call Information Disclosure Vulnerability Windows TCP/IP CVE-2021-24086 Windows TCP/IP Denial of Service Vulnerability Windows TCP/IP CVE-2021-24074 Windows TCP/IP Remote Code Execution Vulnerability Windows TCP/IP CVE-2021-24094 Windows TCP/IP Remote Code Execution Vulnerability Windows Trust Verification API CVE-2021-24080 Windows Trust Verification API Denial of Service Vulnerability
