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Microsoft August 2021 Patch Tuesday fixes 3 zero-days, 44 flaws

Microsoft August 2021 Patch Tuesday fixes 3 zero-days, 44 flaws

Patch Tuesday

Today is Microsoft’s August 2021 Patch Tuesday, and with it comes fixes for three zero-day vulnerabilities and a total of 44 flaws, so please be nice to your Windows admins as they scramble to installed patches.

Microsoft has fixed 44 vulnerabilities (51 including Microsoft Edge) with today’s update, with seven classified as Critical and 37 as Important.

Of the 44 vulnerabilities, 13 are remote code execution, eight are information disclosure, two are denial of service, and four are spoofing vulnerabilities.

For information about the non-security Windows updates, you can read about today’s Windows 10 KB5005033 & KB5005031 cumulative updates.

    Microsoft fixes PrintNightmare and PetitPotam attacks

    Microsoft has released security updates for two eagerly anticipated zero-day vulnerabilities that were discovered over the past month.

    One of the security updates fixes the PrintNightmare vulnerabilities that allow threat actors to gain SYSTEM level privileges simply by connecting to a remote print server under their control.

    Microsoft has fixed this vulnerability by requiring users have administrative privileges to install printer drivers using the Point and Print Windows feature.

    You can find more detailed information about the PrintNightmare vulnerability and the Point and Print mitigations in a dedicated article published today.

    Microsoft also fixed the PetitPotam NTLM relay attack vector that uses the MS-EFSRPC API to force a device to negotiate with a remote relay server under an attacker’s control.

    A threat actor with low privileges could use this attack to take over a domain controller and thus the entire Windows domain.

    Three zero-days fixed, with one actively exploited

    August’s Patch Tuesday includes three zero-day vulnerabilities, with one actively exploited in the wild.

    Microsoft classifies a vulnerability as a zero-day if it is publicly disclosed or actively exploited with no official security updates or released.

    The two publicly disclosed, but not actively exploited, zero-day vulnerabilities are:

    • CVE-2021-36936 – Windows Print Spooler Remote Code Execution Vulnerability
    • CVE-2021-36942 – Windows LSA Spoofing Vulnerability

    The CVE-2021-36942 vulnerability is associated with the PetitPotam NTLM relay attack vector that allows the take over of domain controllers.

    Finally, one actively exploited elevation of privileges vulnerability was discovered by the Microsoft Security Response Center (MSRC) and Microsoft Threat Intelligence Center (MSTIC).

    • CVE-2021-36948 – Windows Update Medic Service Elevation of Privilege Vulnerability

    It is unknown how threat actors used this vulnerability in attacks at this time.

    Recent updates from other companies

    Other vendors who released updates in July include:

    • Adobe released security updates for two products.
    • Android’s August security updates were released last week.
    • Cisco released security updates for numerous products this month.
    • SAP released its August 2021 security updates.
    • VMware released security updates for VMware Workspace ONE 

    The August 2021 Patch Tuesday Security Updates

    Below is the complete list of resolved vulnerabilities and released advisories in the August 2021 Patch Tuesday updates. To access the full description of each vulnerability and the systems that it affects, you can view the full report here.

    Tag CVE ID CVE Title Severity
    .NET Core & Visual Studio CVE-2021-34485 .NET Core and Visual Studio Information Disclosure Vulnerability Important
    .NET Core & Visual Studio CVE-2021-26423 .NET Core and Visual Studio Denial of Service Vulnerability Important
    ASP.NET Core & Visual Studio CVE-2021-34532 ASP.NET Core and Visual Studio Information Disclosure Vulnerability Important
    Azure CVE-2021-36943 Azure CycleCloud Elevation of Privilege Vulnerability Important
    Azure CVE-2021-33762 Azure CycleCloud Elevation of Privilege Vulnerability Important
    Azure Sphere CVE-2021-26428 Azure Sphere Information Disclosure Vulnerability Important
    Azure Sphere CVE-2021-26430 Azure Sphere Denial of Service Vulnerability Important
    Azure Sphere CVE-2021-26429 Azure Sphere Elevation of Privilege Vulnerability Important
    Microsoft Azure Active Directory Connect CVE-2021-36949 Microsoft Azure Active Directory Connect Authentication Bypass Vulnerability Important
    Microsoft Dynamics CVE-2021-36946 Microsoft Dynamics Business Central Cross-site Scripting Vulnerability Important
    Microsoft Dynamics CVE-2021-36950 Microsoft Dynamics 365 (on-premises) Cross-site Scripting Vulnerability Important
    Microsoft Dynamics CVE-2021-34524 Microsoft Dynamics 365 (on-premises) Remote Code Execution Vulnerability Important
    Microsoft Edge (Chromium-based) CVE-2021-30591 Chromium: CVE-2021-30591 Use after free in File System API Unknown
    Microsoft Edge (Chromium-based) CVE-2021-30592 Chromium: CVE-2021-30592 Out of bounds write in Tab Groups Unknown
    Microsoft Edge (Chromium-based) CVE-2021-30597 Chromium: CVE-2021-30597 Use after free in Browser UI Unknown
    Microsoft Edge (Chromium-based) CVE-2021-30594 Chromium: CVE-2021-30594 Use after free in Page Info UI Unknown
    Microsoft Edge (Chromium-based) CVE-2021-30596 Chromium: CVE-2021-30596 Incorrect security UI in Navigation Unknown
    Microsoft Edge (Chromium-based) CVE-2021-30590 Chromium: CVE-2021-30590 Heap buffer overflow in Bookmarks Unknown
    Microsoft Edge (Chromium-based) CVE-2021-30593 Chromium: CVE-2021-30593 Out of bounds read in Tab Strip Unknown
    Microsoft Graphics Component CVE-2021-34530 Windows Graphics Component Remote Code Execution Vulnerability Critical
    Microsoft Graphics Component CVE-2021-34533 Windows Graphics Component Font Parsing Remote Code Execution Vulnerability Important
    Microsoft Office CVE-2021-34478 Microsoft Office Remote Code Execution Vulnerability Important
    Microsoft Office SharePoint CVE-2021-36940 Microsoft SharePoint Server Spoofing Vulnerability Important
    Microsoft Office Word CVE-2021-36941 Microsoft Word Remote Code Execution Vulnerability Important
    Microsoft Scripting Engine CVE-2021-34480 Scripting Engine Memory Corruption Vulnerability Critical
    Microsoft Windows Codecs Library CVE-2021-36937 Windows Media MPEG-4 Video Decoder Remote Code Execution Vulnerability Important
    Remote Desktop Client CVE-2021-34535 Remote Desktop Client Remote Code Execution Vulnerability Critical
    Windows Bluetooth Service CVE-2021-34537 Windows Bluetooth Driver Elevation of Privilege Vulnerability Important
    Windows Cryptographic Services CVE-2021-36938 Windows Cryptographic Primitives Library Information Disclosure Vulnerability Important
    Windows Defender CVE-2021-34471 Microsoft Windows Defender Elevation of Privilege Vulnerability Important
    Windows Event Tracing CVE-2021-34486 Windows Event Tracing Elevation of Privilege Vulnerability Important
    Windows Event Tracing CVE-2021-34487 Windows Event Tracing Elevation of Privilege Vulnerability Important
    Windows Event Tracing CVE-2021-26425 Windows Event Tracing Elevation of Privilege Vulnerability Important
    Windows Media CVE-2021-36927 Windows Digital TV Tuner device registration application Elevation of Privilege Vulnerability Important
    Windows MSHTML Platform CVE-2021-34534 Windows MSHTML Platform Remote Code Execution Vulnerability Critical
    Windows NTLM CVE-2021-36942 Windows LSA Spoofing Vulnerability Important
    Windows Print Spooler Components CVE-2021-34483 Windows Print Spooler Elevation of Privilege Vulnerability Important
    Windows Print Spooler Components CVE-2021-36947 Windows Print Spooler Remote Code Execution Vulnerability Important
    Windows Print Spooler Components CVE-2021-36936 Windows Print Spooler Remote Code Execution Vulnerability Critical
    Windows Services for NFS ONCRPC XDR Driver CVE-2021-36933 Windows Services for NFS ONCRPC XDR Driver Information Disclosure Vulnerability Important
    Windows Services for NFS ONCRPC XDR Driver CVE-2021-26433 Windows Services for NFS ONCRPC XDR Driver Information Disclosure Vulnerability Important
    Windows Services for NFS ONCRPC XDR Driver CVE-2021-36932 Windows Services for NFS ONCRPC XDR Driver Information Disclosure Vulnerability Important
    Windows Services for NFS ONCRPC XDR Driver CVE-2021-26432 Windows Services for NFS ONCRPC XDR Driver Remote Code Execution Vulnerability Critical
    Windows Services for NFS ONCRPC XDR Driver CVE-2021-36926 Windows Services for NFS ONCRPC XDR Driver Information Disclosure Vulnerability Important
    Windows Storage Spaces Controller CVE-2021-34536 Storage Spaces Controller Elevation of Privilege Vulnerability Important
    Windows TCP/IP CVE-2021-26424 Windows TCP/IP Remote Code Execution Vulnerability Critical
    Windows Update CVE-2021-36948 Windows Update Medic Service Elevation of Privilege Vulnerability Important
    Windows Update Assistant CVE-2021-36945 Windows 10 Update Assistant Elevation of Privilege Vulnerability Important
    Windows Update Assistant CVE-2021-26431 Windows Recovery Environment Agent Elevation of Privilege Vulnerability Important
    Windows User Profile Service CVE-2021-34484 Windows User Profile Service Elevation of Privilege Vulnerability Important
    Windows User Profile Service CVE-2021-26426 Windows User Account Profile Picture Elevation of Privilege Vulnerability Important

    Source: https://www.bleepingcomputer.com/news/microsoft/microsoft-august-2021-patch-tuesday-fixes-3-zero-days-44-flaws/