Microsoft September 2021 Patch Tuesday fixes 2 zero-days, 60 flaws

Today is Microsoft's September 2021 Patch Tuesday, and with it comes fixes for two zero-day vulnerabilities and a total of 60 flaws.

Microsoft has fixed 60 vulnerabilities (86 including Microsoft Edge) with today's update, with three classified as Critical, one as Moderate, and 56 as Important.

Microsoft has released a security update for the Windows MSHTML remote code execution vulnerability tracked as CVE-2021-40444.

These attacks distributed malicious Word documents that exploited the CVE-2021-40444 to download and execute a malicious DLL file that installed a Cobalt Strike beacon on the victim's computer.

This beacon allows a threat actor to gain remote access to the device to steal files and spread laterally throughout the network.

With the September 2021 Patch Tuesday updates, Microsoft has released a security update for this vulnerability.

As researchers discovered numerous ways to exploit the bug, including a bypass to mitigations, it is not clear if the security update fixes all of the techniques.

September's Patch Tuesday includes fixes for two zero-day vulnerabilities, with the MSHTML bug actively exploited in the wild.

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

The only actively exploited vulnerability is the Windows MSHTML remote code execution vulnerability, as previously discussed:

Below is the complete list of resolved vulnerabilities and released advisories in the September 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.