Microsoft has released its August edition of Patch Tuesday. This month’s updates have addressed 89 security vulnerabilities in multiple products, features, and roles.
Microsoft Patch Tuesday for August 2023
Microsoft has addressed two zero-day vulnerabilities known to be publicly exploited in this month’s updates. Six of these 89 vulnerabilities are rated as Critical and 68 as Important. Microsoft has addressed 12 vulnerabilities related to Microsoft Edge (Chromium-based) in this month’s Patch Tuesday Edition.
Microsoft has also included two Defense in Depth Updates for Microsoft Office (ADV230003) and Memory Integrity System Readiness Scan Tool (ADV230004).
Microsoft Patch Tuesday, August edition includes updates for vulnerabilities in Microsoft Office and Components, .NET Core, .NET Framework, ASP.NET and Visual Studio, Azure Arc, Azure DevOps, Microsoft Windows Codecs Library, SQL Server, Windows Kernel, Windows LDAP – Lightweight Directory Access Protocol, Windows Message Queuing, Windows Mobile Device Management, Windows Projected File System, and more.
Microsoft has fixed several flaws in multiple software, including Denial of Service (DoS), Elevation of Privilege (EoP), Information Disclosure, Remote Code Execution (RCE), Security Feature Bypass, and Spoofing. The August 2023 Microsoft vulnerabilities are classified as follows:
| Vulnerability Category | Quantity | Severities |
| Spoofing Vulnerability | 12 | Important: 12 |
| Denial of Service Vulnerability | 8 | Important: 8 |
| Elevation of Privilege Vulnerability | 18 | Important: 18 |
| Information Disclosure Vulnerability | 10 | Important: 10 |
| Security Feature Bypass Vulnerability | 4 | Important: 3 |
| Remote Code Execution Vulnerability | 23 | Critical: 6 Important: 17 |
Zero-day Vulnerabilities Patched in August Patch Tuesday Edition
CVE-2023-36884: Windows Search Remote Code Execution Vulnerability
Microsoft released OS updates in the last month’s edition to address the vulnerability. In this month’s updates, Microsoft has released an additional Defense in Depth Update (ADV230003) to stop the attack chain used in the exploitation of the vulnerability.
Microsoft has updated the title from Office and Windows HTML Remote Code Execution Vulnerability to Windows Search Remote Code Execution Vulnerability in this month’s update.
An attacker may exploit the vulnerability in an email or instant message attack scenario by sending a specially crafted file. An attacker may plant a malicious file evading Mark of the Web (MOTW) defenses which can result in code execution on the victim system.
CVE-2023-38180: .NET and Visual Studio Denial of Service Vulnerability
The vulnerability may allow an attacker to perform a denial-of-service attack on a target system in a low-complexity attack without special privileges.
Microsoft has not provided any additional information regarding the vulnerability in the latest advisory.
CISA has added the CVE-2023-38180 to its Known Exploited Vulnerabilities Catalog requesting users to patch it before Aug 30, 2023.
Other Critical Severity Vulnerabilities Patched in August Patch Tuesday Edition
CVE-2023-29328 & CVE-2023-29330: Microsoft Teams Remote Code Execution Vulnerability
An attacker is required to trick a user into joining a Teams meeting set up by them. It would allow the attacker to perform remote code execution in the context of the victim user. A successful remote attack performed by an attacker would enable them to access and alter user information. The attacker requires no privileges to perform the exploit.
CVE-2023-36910, CVE-2023-36911, & CVE-2023-35385: Microsoft Message Queuing Remote Code Execution Vulnerability
Message Queuing (MSMQ) is a protocol developed by Microsoft to ensure reliable communication between Windows computers across different networks, even when a host is temporarily not connected (by maintaining a message queue of undelivered messages).
To exploit this vulnerability, an attacker must send a specially crafted malicious MSMQ packet to an MSMQ server. An unauthenticated attacker may perform remote code execution on the target server by successfully exploiting the vulnerability.
CVE-2023-36895: Microsoft Outlook Remote Code Execution Vulnerability
To exploit the vulnerability, an attacker must convince a victim to download and open a specially crafted file from a website, leading to a local computer attack.
Other Microsoft Vulnerability Highlights
- CVE-2023-35359 is an elevation of privilege vulnerability that may allow an attacker to gain SYSTEM privileges. An attacker with local access to the targeted machine and the user may create folders and performance traces on the device with restricted privileges that normal users have by default.
- CVE-2023-36900 is an elevation of privilege vulnerability in the Windows Common Log File System Driver. Successful exploitation of the vulnerability may allow an attacker to gain SYSTEM privileges.
- CVE-2023-35380, CVE-2023-35382, and CVE-2023-35386 are elevation of privilege vulnerabilities in the Windows Kernel. Successful exploitation of the vulnerabilities may allow an attacker to gain SYSTEM privileges.
- CVE-2023-35384 is a security feature bypass vulnerability in the Windows HTML Platforms. To exploit the vulnerability, an attacker must send the user a malicious file and convince them to open it. The vulnerability arises when the MSHTML platform fails to validate the correct Security Zone of requests for specific URLs. An attacker may exploit this to cause a user to access a URL in a less restricted Internet Security Zone than intended.
- CVE-2023-35388 and CVE-2023-38182 are remote code execution vulnerabilities affecting Microsoft Exchange Server. To exploit these vulnerabilities, the attacker must be authenticated with LAN access and have credentials for a valid Exchange user. On successful exploitation, an attacker may perform remote code execution via a PowerShell remoting session.
Microsoft Release Summary
This month’s release notes cover multiple Microsoft product families and products/versions affected, including, but not limited to, Memory Integrity System Readiness Scan Tool, Microsoft Exchange Server, Microsoft Teams, Windows Reliability Analysis Metrics Calculation Engine, Windows Fax and Scan Service, Windows HTML Platform, Windows Bluetooth A2DP driver, Microsoft Dynamics, Azure HDInsights, Reliability Analysis Metrics Calculation Engine, Microsoft WDAC OLE DB provider for SQL, Windows Group Policy, Tablet Windows User Interface, ASP.NET, Windows Common Log File System Driver, Windows System Assessment Tool, Windows Cloud Files Mini Filter Driver, Windows Wireless Wide Area Network Service, Windows Cryptographic Services, Windows Hyper-V, Windows Smart Card, Dynamics Business Central Control, and Windows Defender.
EVALUATE Vendor-Suggested Mitigation with Policy Compliance (PC)
Qualys Policy Compliance’s Out-of-the-Box Mitigation or Compensatory Controls reduce the risk of a vulnerability being exploited because the remediation (fix/Patch) cannot be done now; these security controls are not recommended by any industry standards such as CIS, DISA-STIG.
Qualys Policy Compliance team releases these exclusive controls based on Vendor-suggested Mitigation/Workaround.
Mitigation refers to a setting, common configuration, or general best-practice existing in a default state that could reduce the severity of exploitation of a vulnerability.
A workaround is a method, sometimes used temporarily, for achieving a task or goal when the usual or planned method isn’t working. Information technology often uses a workaround to overcome hardware, programming, or communication problems. Once a problem is fixed, a workaround is usually abandoned.
The following Qualys Policy Compliance Control IDs (CIDs) and System Defined Controls (SDC) has been updated to support Microsoft recommended mitigation(s) for this Patch Tuesday:
CVE-2023-35378: Windows Projected File System Elevation of Privilege Vulnerability
This vulnerability has a CVSS:3.1 7.0 / 6.1
Policy Compliance Control IDs (CIDs):
- 11511 List of installed features on the system
CVE-2023-35385, CVE-2023-36910, & CVE-2023-36911: Microsoft Message Queuing Remote Code Execution Vulnerability
This vulnerability has a CVSS:3.1 9.8 / 8.5
Policy Compliance Control IDs (CIDs):
- 4030 Status of the ‘Windows Message Queuing Service’
- 14916 Status of Windows Services
- 14297 Status of the open network connections and listening ports (Qualys Agent only)
CVE-2023-21709: Microsoft Exchange Server Elevation of Privilege Vulnerability
This vulnerability has a CVSS:3.1 9.8 / 8.5
Policy Compliance Control IDs (CIDs):
- 13515 List installed IIS modules
The following QQL will return a posture assessment for the CIDs for this Patch Tuesday:
control.id: [4030,14916,14297,11511,13515]
EXECUTE Mitigation Using Qualys Custom Assessment and Remediation (CAR)
Qualys Custom Assessment and Remediation (CAR) can be leveraged to execute mitigation steps provided by MSRC on vulnerable assets.
CVE-2023-35378: Windows Projected File System Elevation of Privilege Vulnerability
This vulnerability has a CVSSv3.1 score of 7.0/10. 
CVE-2023-36910, CVE-2023-36911, & CVE-2023-35385: Microsoft Message Queuing Remote Code Execution Vulnerability
This vulnerability has a CVSSv3.1 score of 9.8/10. 
CVE-2023-21709: Microsoft Exchange Server Elevation of Privilege Vulnerability
Note: This is Post Patch Activity This vulnerability has a CVSSv3.1 score of 9.8/10. 
Visit the August 2023 Security Updates page to access the full description of each vulnerability and the systems it affects.
Qualys customers can scan their network with QIDs 110443, 110444, 110445, 378744, 378755, 50127, 92042, 92043, 92044, 92045, 92046, 92047, 92049, 92052, and 92053 to detect vulnerable assets.
Please continue to follow Qualys Threat Protection for more coverage of the latest vulnerabilities.
References:
https://msrc.microsoft.com/update-guide/releaseNote/2023-Aug
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2023-36884
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2023-38180
https://msrc.microsoft.com/update-guide/en-US/vulnerability/ADV230003
https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2023-29330
https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2023-29328
https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2023-36910
https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2023-36911
https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2023-35385
https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2023-36895