JPCERT-AT-2021-0045
                                                             JPCERT/CC
                                                            2021-10-13

                 <<< JPCERT/CC Alert 2021-10-13 >>>

          Microsoft Releases October 2021 Security Updates

       https://www.jpcert.or.jp/english/at/2021/at210045.html


I. Overview
Microsoft has released October 2021 Security Updates to address the
vulnerabilities in their products. Remote attackers leveraging
these vulnerabilities may be able to execute arbitrary code. It is
recommended to check the information provided by Microsoft and
apply the updates.

    Microsoft Corporation
    October 2021 Security Updates
    https://msrc.microsoft.com/update-guide/en-us/releaseNote/2021-Oct

    Microsoft Corporation
    Microsoft Security Updates for October 2021 (Monthly) (Japanese)
    https://msrc-blog.microsoft.com/2021/10/12/202110-security-updates/

According to Microsoft, among these vulnerabilities, an elevation of
privilege vulnerability in Win32k (CVE-2021-40449) has been confirmed
to be exploited in the wild. Please consider applying the security
update programs as soon as possible.

    CVE-2021-40449
    Win32k Elevation of Privilege Vulnerability
    https://msrc.microsoft.com/update-guide/vulnerability/CVE-2021-40449

In addition, according to Microsoft, information on the following
vulnerabilities have been publicly disclosed while the exploit has not
been observed.

    CVE-2021-41335
    Windows Kernel Elevation of Privilege Vulnerability
    https://msrc.microsoft.com/update-guide/vulnerability/CVE-2021-41335

    CVE-2021-41338
    Windows AppContainer Firewall Rules Security Feature Bypass Vulnerability
    https://msrc.microsoft.com/update-guide/vulnerability/CVE-2021-41338

    CVE-2021-40469
    Windows DNS Server Remote Code Execution Vulnerability
    https://msrc.microsoft.com/update-guide/vulnerability/CVE-2021-40469


II. Solution
Please apply the security update programs through Microsoft Update,
Windows Update, etc. as soon as possible.

    Microsoft Update Catalog
    https://www.catalog.update.microsoft.com/

    Windows Update: FAQ
    https://support.microsoft.com/en-us/help/12373/windows-update-faq


III. References
    Microsoft Corporation
    Release Notes
    https://msrc.microsoft.com/update-guide/releaseNote


If you have any information regarding this alert, please contact
JPCERT/CC.

======================================================================
JPCERT Coordination Center (Early Warning Group)
MAIL: ew-info@jpcert.or.jp
https://www.jpcert.or.jp/english/