Critical Patches Issued for Microsoft Products, May 11, 2021

DESCRIPTION:
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.

IMPACT:
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/en-us

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.

SYSTEM AFFECTED:
* .NET Core & Visual Studio
* HTTP.sys
* Internet Explorer
* Microsoft Accessibility Insights for Web
* Microsoft Bluetooth Driver
* Microsoft Dynamics Finance & Operations
* Microsoft Exchange Server
* Microsoft Graphics Component
* Microsoft Office
* Microsoft Office Access
* Microsoft Office Excel
* Microsoft Office SharePoint
* Microsoft Office Word
* Microsoft Windows Codecs Library
* Microsoft Windows IrDA
* Open Source Software
* Role: Hyper-V
* Skype for Business and Microsoft Lync
* Visual Studio
* Visual Studio Code
* Windows Container Isolation FS Filter Driver
* Windows Container Manager Service
* Windows Cryptographic Services
* Windows CSC Service
* Windows Desktop Bridge
* Windows OLE
* Windows Projected File System FS Filter
* Windows RDP Client
* Windows SMB
* Windows SSDP Service
* Windows WalletService
* Windows Wireless Networking

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.

REFERENCES:
* https://msrc.microsoft.com/update-guide
* https://msrc.microsoft.com/update-guide/releaseNote/2021-May