Critical Patches Issued for Microsoft Products, July 13, 2021

MS-ISAC ADVISORY NUMBER:

2021-089

DATE(S) ISSUED:

07/13/2021

OVERVIEW:

Multiple vulnerabilities have been discovered in Microsoft products, the most severe of which could allow for arbitrary code execution in the context of the logged on user. Depending on the privileges associated with the user, an attacker could then install programs; view, change, or delete data; or create new accounts with full user rights. Users whose accounts are configured to have fewer user rights on the system could be less impacted than those who operate with administrative user rights.

THREAT INTELLIGENCE:

There are reports that the Windows Print Spooler Remote Code Execution Vulnerability (CVE-2021-34527), Windows Kernel Elevation of Privilege Vulnerabilities (CVE-2021-33771, CVE-2021-31979) and Scripting Engine Memory Corruption Vulnerability (CVE-2021-34448) are actively being exploited in the wild.

RISK:

Government:
Large and medium government entitiesHIGH
Small governmentMEDIUM
Businesses:
Large and medium business entitiesHIGH
Small business entitiesMEDIUM
Home Users:
LOW

TECHNICAL SUMMARY:

Multiple vulnerabilities have been discovered in Microsoft products, the most severe of which could allow for arbitrary code execution. A full list of all vulnerabilities can be found at the link below: https://msrc.microsoft.com/update-guide Successful exploitation of the most severe of these vulnerabilities could result in an attacker gaining the same privileges as the logged-on user. Depending on the privileges associated with the user, an attacker could then install programs; view, change, or delete data; or create new accounts with full user rights.

RECOMMENDATIONS:

We recommend the following actions be taken:

  • Apply appropriate patches or appropriate mitigations provided by Microsoft to vulnerable systems immediately after appropriate testing.
  • Run all software as a non-privileged user (one without administrative privileges) to diminish the effects of a successful attack.
  • Remind all users not to visit untrusted websites or follow links provided by unknown or untrusted sources.
  • Inform and educate users regarding the threats posed by hypertext links contained in emails or attachments especially from untrusted sources.
  • Apply the Principle of Least Privilege to all systems and services.

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