Critical Patches Issued for Microsoft Products, August 10, 2021

MS-ISAC ADVISORY NUMBER:

2021-102

DATE(S) ISSUED:

08/10/2021

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 no reports of these vulnerabilities being exploited in the wild.

**August 10 - UPDATED THREAT INTELLIGENCE:
Three zero-day vulnerabilities were issued August 10, 2021. CVE-2021-36936 Windows Print Spooler remote code execution vulnerability and CVE-2021-36942 Windows LSA spoofing vulnerability have been reported as publicly disclosed vulnerabilities. CVE-2021-36948 Windows Update Medic Service elevation of privilege vulnerability has been reported as actively exploited.

SYSTEMS AFFECTED:

  • .NET Core & Visual Studio
  • ASP .NET
  • Azure
  • Azure Sphere
  • Microsoft Azure Active Directory Connect
  • Microsoft Dynamics
  • Microsoft Graphics Component
  • Microsoft Office
  • Microsoft Office SharePoint
  • Microsoft Office Word
  • Microsoft Scripting Engine
  • Microsoft Windows Codecs Library
  • Remote Desktop Client
  • Windows Bluetooth Service
  • Windows Cryptographic Services
  • Windows Defender
  • Windows Event Tracing
  • Windows Media
  • Windows MSHTML Platform
  • Windows NTLM
  • Windows Print Spooler Components
  • Windows Services for NFS ONCRPC XDR Driver
  • Windows Storage Spaces Controller
  • Windows TCP/IP
  • Windows Update
  • Windows Update Assistant
  • Windows User Profile Service

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. 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.

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 rights) 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 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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