August Patch Tuesday 2021 Fixes 44 Vulnerabilities Including Weaponized Threat

Microsoft Releases August 2021 Patch Tuesday Fixes

There are 7 Critical and 37 Important fixes in this August Patch Tuesday for Microsoft Windows and Windows components, Office, .NET Core and Visual Studio, Windows Defender, Windows Update and Update Assistant, Azure, and Microsoft Dynamics.

Year 2 Extended Support – Windows 7 and Windows Server 2008 (including R2) have received some updates this month, with one currently Weaponized.

1. Windows 7 – 4 Critical and 8 Important vulnerabilities fixed
2. Windows 2008 R2 – 4 Critical and 9 Important vulnerabilities fixed

Robert Brown, Head of Customer Success for Syxsense said, “There are a number of extremely serious threats to deal with this month, and although there are less than half the number we have been facing just a couple months ago, it has never been more important to deploy these update to protect your environment.”

Top August 2021 Patches and Vulnerabilities

Based on the Vendor Severity and CVSS Score, we have made a few recommendations below. As usual, we recommend entering the CVE numbers below into your patch management solution and deploying as soon as possible. 

1. CVE-2021-36948: Windows Update Medic Service Elevation of Privilege Vulnerability

The vulnerability allows a local user to escalate privileges on the system, due to a boundary error within the Windows Update Medic Service. A local user can run a specially crafted program to execute arbitrary code with elevated privileges.

We are also extremely concerned as this was discovered by Microsoft Security Response Center (MSRC) / Microsoft Threat Intelligence Center which could indicate this would be turned into a ransomware attack.

Syxscore

• Vendor Severity: Important
• CVSS: 7.8
• Weaponized: Yes
• Public Aware: No
• Countermeasure: No 

Syxscore Risk Alert

• Attack Vector: Local
• Attack Complexity: Low
• Privileges: Low
• User Interaction: None
• Scope (Jump Point): No

2. CVE-2021-34535: Remote Desktop Client Remote Code Execution Vulnerability

In the case of a Remote Desktop connection, an attacker with control of a Remote Desktop Server could trigger a remote code execution (RCE) on the machine when a victim connects to the attacking server with the vulnerable Remote Desktop Client.

In the case of Hyper-V, a malicious program running in a guest VM could trigger guest-to-host RCE by exploiting this vulnerability in the Hyper-V Viewer when a victim running on the host connects to the attacking Hyper-V guest.

Microsoft advise this exploit is more likely.

Syxscore

• Vendor Severity: Critical
• CVSS: 8.8
• Weaponized: No
• Public Aware: No
• Countermeasure: No

Syxscore Risk Alert

• Attack Vector: Network
• Attack Complexity: Low
• Privileges: None
• User Interaction: Required
• Scope (Jump Point): No

3. CVE-2021-36936: Windows Print Spooler Remote Code Execution Vulnerability

The vulnerability allows a remote attacker to execute arbitrary code on the target system and successful exploitation of this vulnerability may result in complete compromise of vulnerable system.

Microsoft advise this exploit is more likely.

Syxscore

• Vendor Severity: Critical
• CVSS: 8.8
• Weaponised: No
• Public Aware: Yes
• Countermeasure: No 

Syxscore Risk Alert

• Attack Vector: Network
• Attack Complexity: Low
• Privileges: Low
• User Interaction: None
• Scope (Jump Point): No

Syxsense Recommendations

Based on the vendor severity and CVSS Score, we have made a few recommendations below which you should prioritize this month. Please pay close attention to any of these which are publicly aware or weaponized.

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