March 2023 Patch Tuesday comes with fixes for 83 vulnerabilities, including 2 zero days

The third Patch Tuesday of the season doesn't fail to surprise us at all. Keeping the trend intact, March 2023’s Patch Tuesday lists fixes for 83 vulnerabilities: two of them zero days and nine of them rated critical. With both of the zero-days 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.

March 2023 Patch Tuesday: Security updates lineup  

Security updates were released for the following products, features, and roles:

  • Azure

  • Client Server Run-time Subsystem (CSRSS)

  • Internet Control Message Protocol (ICMP)

  • Microsoft Bluetooth Driver

  • Microsoft Dynamics

  • Microsoft Edge (Chromium-based)

  • Microsoft Graphics Component

  • Microsoft Office Excel

  • Microsoft Office Outlook

  • Microsoft Office SharePoint

  • Microsoft OneDrive

  • Microsoft PostScript Printer Driver

  • Microsoft Printer Drivers

  • Microsoft Windows Codecs Library

  • Office for Android

  • Remote Access Service Point-to-Point Tunneling Protocol

  • Role: DNS Server

  • Role: Windows Hyper-V

  • Service Fabric

  • Visual Studio

  • Windows Accounts Control

  • Windows Bluetooth Service

  • Windows Central Resource Manager

  • Windows Cryptographic Services

  • Windows Defender

  • Windows HTTP Protocol Stack

  • Windows HTTP.sys

  • Windows Internet Key Exchange (IKE) Protocol

  • Windows Kernel

  • Windows Partition Management Driver

  • Windows Point-to-Point Protocol over Ethernet (PPPoE)

  • Windows Remote Procedure Call

  • Windows Remote Procedure Call Runtime

  • Windows Resilient File System (ReFS)

  • Windows Secure Channel

  • Windows SmartScreen

  • Windows TPM

  • Windows Win32K

 

Learn more in the MSRC’s release notes.

Two zero-day vulnerabilities patched  

March’s Patch Tuesday comes with an update for an actively exploited zero-day vulnerability.

  •  CVE-2023-23397 - Microsoft Outlook Elevation of Privilege Vulnerability

This privilege elevation bug in Microsoft Outlook leverages phishing attacks and forces the target device to connect to a remote URL via specially crafted emails. Once connected, the devices are forced to transmit the Windows account's Net-NTLMv2 hash.

Per Microsoft's advisory, "External attackers could send specially crafted emails that will cause a connection from the victim to an external UNC location of attackers' control. This will leak the Net-NTLMv2 hash of the victim to the attacker who can then relay this to another service and authenticate as the victim."

 While the vulnerability is being actively exploited, it hasn't been publicly disclosed yet.

  •  CVE-2023-24880 - Windows SmartScreen Security Feature Bypass Vulnerability

 Speaking about this zero-day, Microsoft's advisory reads, "An attacker can craft a malicious file that would evade Mark of the Web (MOTW) defenses, resulting in a limited loss of integrity and availability of security features such as Protected View in Microsoft Office, which rely on MOTW tagging."

While this vulnerability had been exploited previously for malware distribution, it can be exploited and accessed in the systems without triggering Microsoft's Mark of the Web—a security feature that prevents malicious files and attachments from being downloaded or opened.

This vulnerability is being actively exploited, and the exploit been disclosed publicly.

Third-party updates released after last month’s Patch Tuesday  

Third-party vendors such as Google, Fortinet, Apple, Cisco, and Veeam also released updates this March.

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:

  • 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.

  • Create a restore point—a backup or image that captures the state of the machines—before deploying big updates like those from Patch Tuesday.

  • 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.

  • 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.

  • 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.

  • 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.

  • 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.

  • Run patch reports to get a detailed view of the health status of your endpoints.

  • 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.

  • Install the latest updates and feature packs before deeming your back-to-office machines fit for production.

  • 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!