Welcome to May 2023’s Patch Tuesday, which lists fixes for 38 vulnerabilities, including three zero days and six critical vulnerabilities. With two of the zero-day vulnerabilities being actively exploited, admins need to implement these patches as soon as possible.
After an initial discussion about this month’s updates, we’ll offer our advice for devising a plan to handle patch management in a hybrid work environment. You can also register for our free Patch Tuesday webinar and listen to our experts break down Patch Tuesday updates in detail.
What is Patch Tuesday?
Patch Tuesday falls on the second Tuesday of every month. On this day, Microsoft releases security and non-security updates for its operating system and other related applications. Since Microsoft has upheld this process of releasing updates in a periodic manner, IT admins expect these updates and have time to gear up for them.
Why is Patch Tuesday important?
Important security updates and patches to fix critical bugs or vulnerabilities are released on Patch Tuesday. Usually zero-day vulnerabilities are also fixed during Patch Tuesday unless the vulnerability is critical and highly exploited, in which case an out-of-band security update is released to address that particular vulnerability.
May 2023 Patch Tuesday: Security updates lineup
Security updates were released for the following products, features, and roles:
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Microsoft Teams
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Windows SMB
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Microsoft Graphics Component
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Windows NTLM
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Windows NFS Portmapper
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Windows Win32K
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Windows Secure Socket Tunneling Protocol (SSTP)
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Windows Installer
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Remote Desktop Client
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Windows Secure Boot
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Windows NFS Portmapper
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Reliable Multicast Transport Driver (RMCAST)
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Windows Network File System
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Windows Remote Procedure Call Runtime
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Reliable Multicast Transport Driver (RMCAST)
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Microsoft Bluetooth Driver
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Windows iSCSI Target Service
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Windows Backup Engine
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Microsoft Bluetooth Driver
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Microsoft Bluetooth Driver
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Windows Kernel
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Microsoft Office SharePoint
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Microsoft Office Excel
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Microsoft Office SharePoint
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Microsoft Office SharePoint
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Windows Secure Boot
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Windows LDAP – Lightweight Directory Access Protocol
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Windows RDP Client
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Windows MSHTML Platform
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Windows OLE
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Microsoft Office Access
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Microsoft Office Word
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Windows Win32K
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Visual Studio Code
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Microsoft Windows Codecs Library
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Microsoft Windows Codecs Library
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SysInternals
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Microsoft Office
Learn more in the MSRC’s release notes.
Three zero-day vulnerabilities patched
May’s Patch Tuesday comes with updates for two actively exploited zero-day vulnerabilities.
- CVE-2023-24932 – Secure Boot Security Feature Bypass Vulnerability
This actively exploited vulnerability can be leveraged by attackers to bypass Secure Boot. In its advisory, Microsoft stated, “To exploit the vulnerability, an attacker who has physical access or Administrative rights to a target device could install an affected boot policy.”
As for protection against this vulnerability, Microsoft has further stated, “The security update addresses the vulnerability by updating the Windows Boot Manager, but is not enabled by default. Additional steps are required at this time to mitigate the vulnerability. Please refer to the following for steps to determine the impact on your environment: KB5025885: How to manage the Windows Boot Manager revocations for Secure Boot changes associated with CVE-2023-24932.”
- CVE-2023-29336 – Win32k Elevation of Privilege Vulnerability
This zero-day vulnerability in the Win32k Kernel driver is the second actively exploited vulnerability to be patched this Patch Tuesday. However, the exploit hasn’t been disclosed publicly.
Per Microsoft advisory, “An attacker who successfully exploited this vulnerability could gain SYSTEM privileges.”
- CVE-2023-29325 – Windows OLE Remote Code Execution Vulnerability
Fortunately, this zero day vulnerability in Windows OLE is not being actively exploited but can be exploited via email attacks. Microsoft stated in its advisory that the attack vector for this vulnerability is the Preview Pane and “Successful exploitation of this vulnerability requires an attacker to win a race condition and also to take additional actions prior to exploitation to prepare the target environment.”
The vulnerability can be exploited if the malicious email is opened either via an affected version of Microsoft Outlook or a preview of the email is being displayed via Outlook.
To prevent this vulnerability from being exploited, Microsoft has recommended users to read emails in plain text format. You can refer here to learn more on the workaround.
Third-party updates released after last month’s Patch Tuesday
Third-party vendors such as Google, Apple, Cisco, CISA, and SAP released updates in May 2023.
Best practices to handle patch management in a hybrid work environment
Most organizations have opted to embrace remote work even after they have been cleared to return to the office. This decision poses various challenges to IT admins, especially in terms of managing and securing distributed endpoints.
Here are a few pointers to simplify the process of remote patching:
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Disable automatic updates because one faulty patch could bring down the whole system. IT admins can educate end users on how to disable automatic updates on their machines. Patch Manager Plus and Endpoint Central also have a dedicated patch, 105427, that can be deployed to endpoints to ensure that automatic updates are disabled.
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Create a restore point—a backup or image that captures the state of the machines—before deploying big updates like those from Patch Tuesday.
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Establish a patching schedule and keep end users informed about it. It is recommended to set up a time for deploying patches and rebooting systems. Let end users know what needs to be done on their end for trouble-free patching.
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Test the patches on a pilot group of systems before deploying them to the production environment. This will ensure that the patches do not interfere with the workings of other applications.
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Since many users are working from home, they all might be working different hours; in this case, you can allow end users to skip deployment and scheduled reboots. This will give them the liberty to install updates at their convenience and avoid disrupting their work. Our patch management products come with options for user-defined deployment and reboot.
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Most organizations are deploying patches using a VPN. To stop patch tasks from eating up your VPN bandwidth, install Critical patches and security updates first. You might want to hold off on deploying feature packs and cumulative updates since they are bulky updates and consume a lot of bandwidth.
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Schedule the non-security updates and security updates that are not rated Critical to be deployed after Patch Tuesday, such as during the third or fourth week of the month. You can also choose to decline certain updates if you feel they are not required in your environment.
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Run patch reports to get a detailed view of the health status of your endpoints.
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For machines belonging to users returning to the office after working remotely, check if they are compliant with your security policies. If not, quarantine them.
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Install the latest updates and feature packs before deeming your back-to-office machines fit for production.
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Take inventory of and remove apps that are now obsolete for your back-to-office machines, like remote collaboration software.
With Endpoint Central or Patch Manager Plus, you can completely automate the entire process of patch management, from testing patches to deploying them. You can also tailor patch tasks according to your current needs. For a hands-on experience with either of these products, try a free, 30-day trial and keep thousands of applications patched and secure.
Want to learn more about Patch Tuesday updates? Join our experts as they break down this month’s Patch Tuesday updates and offer in-depth analysis. You can also ask our experts questions and get answers to all your Patch Tuesday questions. Register for our free Patch Tuesday webinar.
Ready, get set, patch!
