Threat Response – Multiple critical zero day vulnerabilities in Microsoft Windows



On Tuesday June 8th (“Patch Tuesday”) Microsoft released patches for multiple vulnerabilities, among which seven zero-day vulnerabilities. Of these, six are actively being exploited [1]. We advise to install these patches as soon as possible.

On Tuesday June 8th Microsoft released patches for a large number of vulnerabilities, of which seven zero-day vulnerabilities. The zero-day vulnerabilities are tracked under the following CVE-numbers:

  • CVE-2021-31955 – Windows Kernel Information Disclosure Vulnerability
  • CVE-2021-31956 – Windows NTFS Elevation of Privilege Vulnerability
  • CVE-2021-33739 – Microsoft DWM Core Library Elevation of Privilege Vulnerability
  • CVE-2021-33742 – Windows MSHTML Platform Remote Code Execution Vulnerability
  • CVE-2021-31199 – Microsoft Enhanced Cryptographic Provider Elevation of Privilege Vulnerability
  • CVE-2021-31201 – Microsoft Enhanced Cryptographic Provider Elevation of Privilege Vulnerability
  • CVE-2021-31968 – Windows Remote Desktop Services Denial of Service Vulnerability

In [2] you can find an overview of all patched vulnerabilities including their CVSS-score. Microsoft’s official release notes can be found at [3].

Of the patched vulnerabilities, several are very severe. Some of them, at least six, are actively being exploited.
Therefore we assess the impact as high.

Because some of these vulnerabilities are under active abuse, we estimate the risk as high.

What should you do?
Install the updates that were released yesterday as soon as possible.

What will Northwave do?
Northwave is researching the possibilities of monitoring for exploit attempts. When possible, we will add these capabilities to the Northwave Detection Platform.
Northwave will monitor any developments regarding this vulnerability. If new critical information about this threat arises we will reach out to you. If you need additional information you can call us by phone or send us an email.

E-mail: [email protected]
Do you have an incident right now? Call our CERT number: +31 (0)85 043 7909 or 0800-1744 (alleen vanuit Nederland)

Disclaimer applies, see below.




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