CVE-2022-41073: Urgent Windows Print Spooler Privilege Escalation Advisory
Microsoft Windows Print Spooler contains an unspecified vulnerability that allows an attacker to gain SYSTEM-level privileges.
FREQUENTLY ASKED
What is CVE-2022-41073 and why does it matter?
CVE-2022-41073 is a high-severity elevation of privilege vulnerability in the Windows Print Spooler. It is critical because it allows a local, low-privileged attacker to gain SYSTEM-level access, the highest level of control on a Windows machine. With an EPSS score indicating significant threat activity and known ransomware use, this flaw is particularly dangerous when used as a secondary stage in a multi-vector attack targeting organizational infrastructure.
Which versions of the product are affected?
This vulnerability affects a wide range of Microsoft Windows versions, including legacy and modern releases. Specifically, builds 10.0.17763.0, 10.0.19045.0, 10.0.22621.0, and various iterations of Windows Server (2012, 2016, 2019, 2022) and older versions like 6.1.7601.0 and 6.3.9600.0 are impacted. Administrators must verify their specific build numbers against the vendor’s list to ensure they are not running a vulnerable version.
Whether a patch has been released?
Yes, Microsoft released a formal security update to address CVE-2022-41073 on November 8, 2022. The patch specifically remediates the CWE-787 out-of-bounds write vulnerability within the Print Spooler service. Organizations should immediately access the Microsoft Security Response Center (MSRC) update guide or use Windows Update Services to download and deploy the necessary cumulative updates or standalone security patches.
What the remediation deadline is and what it means for compliance?
The remediation deadline is December 9, 2022. For federal agencies and organizations following CISA’s Binding Operational Directive (BOD) 22-01, this date represents the mandatory deadline for patching to mitigate known exploited vulnerabilities. Failing to meet this deadline leaves systems exposed to active threats and signifies a failure in regulatory compliance, potentially leading to increased risk of data breaches and administrative oversight.
How to check if an instance/deployment is affected?
To determine if an instance is affected, administrators should check the current build and patch level of their Windows installation. Compare the system's 'OS Build' number (found via the 'winver' command) against the patched build numbers listed in the MSRC advisory for CVE-2022-41073. Additionally, security teams can use vulnerability scanners or check for the specific KB articles associated with the November 2022 updates.
CVE-2022-41073 is a high-severity Elevation of Privilege (EoP) vulnerability identified within the Microsoft Windows Print Spooler service. With a CVSS score of 7.8 and categorized as a CWE-787 Out-of-bounds Write, this flaw poses a significant threat to organizational security. The vulnerability has been confirmed for active exploitation in the wild and is associated with known ransomware operations. All affected Windows environments must be patched by the remediation deadline of December 9, 2022, to maintain compliance and mitigate the risk of total system compromise.
Vulnerability Profile
Field
Value
CVE ID
CVE-2022-41073
Affected Product & Versions
Windows 10 (17763.0, 19043.0, 19045.0, 10240.0, 14393.0), Windows 11 (22621.0), Windows Server (20348.0), Windows 7, 8.1
Technical Deep Dive: Understanding CWE-787 and the Print Spooler
The Windows Print Spooler (spoolsv.exe) is a legacy service responsible for managing the printing process, including the handling of print jobs and the loading of printer drivers. Historically, this component has been a frequent target for researchers and threat actors alike due to its high privileges (running as SYSTEM) and complex codebase. CVE-2022-41073 leverages a fundamental memory management error categorized under CWE-787: Out-of-bounds Write.
The Mechanics of Out-of-Bounds Write
An out-of-bounds write occurs when a program writes data past the end of the intended buffer or before the beginning of the buffer. In the context of the Print Spooler, this usually happens during the processing of malformed print requests or driver configurations. When the spoolsv.exe service fails to properly validate the size of the data being written to memory, an attacker can overwrite adjacent memory locations.
By carefully crafting the overflow, an attacker can corrupt sensitive data structures, such as function pointers or return addresses on the stack. In the case of CVE-2022-41073, the vulnerability allows a local user with minimal privileges to redirect the execution flow of the Spooler service. Since the Spooler runs with NT AUTHORITY\SYSTEM privileges, any code executed through this redirection also inherits those highest-level permissions.
Attack Surface and Blast Radius
The attack surface for CVE-2022-41073 is localized but pervasive. Because the Print Spooler service is enabled by default on most Windows installations, nearly every unpatched workstation and server in an enterprise environment represents a potential point of escalation.
The "blast radius" is defined by the SSVC Technical Impact of "total." Once an attacker achieves SYSTEM-level access, they have unrestricted control over the local machine. This includes the ability to install malicious software, manipulate the file system, disable security monitoring tools (such as EDR agents), and extract credentials from memory (e.g., via LSASS). This makes the vulnerability an ideal tool for lateral movement and the final stage of a ransomware infection chain, where attackers seek to maximize their foothold before deploying encryption payloads.
Who Is Affected: Windows Ecosystem and Compliance Requirements
This vulnerability impacts a vast array of Windows operating systems. The affected versions range from legacy systems like Windows 7 (build 6.1.7601.0) and Windows 8.1 (build 6.3.9600.0) to modern iterations including Windows 10 and Windows 11. Crucially, Windows Server environments, including 2012, 2016, 2019, and 2022, are also within the scope of impact.
For organizations operating within the United States federal civilian executive branch, or those that align with CISA standards, compliance is mandatory. Under CISA BOD 22-01, CVE-2022-41073 was added to the Known Exploited Vulnerabilities (KEV) catalog. The remediation deadline of December 9, 2022, serves as a hard cutoff for applying patches. Failure to remediate by this date is considered a significant security deficiency, as the vulnerability is actively being used by threat actors to facilitate cyberattacks, including ransomware.
Official Remediation Steps: Patching and Verification
Microsoft has provided a comprehensive set of security updates to address this flaw. Follow these steps to secure your environment:
Identify Vulnerable Assets: Use centralized management tools (like Microsoft Endpoint Configuration Manager or WSUS) to identify systems running unpatched versions of Windows. Pay close attention to the build numbers listed in the Vulnerability Profile.
Apply Cumulative Updates: For most modern Windows versions, the fix for CVE-2022-41073 is included in the November 2022 Monthly Rollup or Security Only updates. Deployment should be prioritized for Domain Controllers and Print Servers.
Verify Installation: After rebooting, verify that the patch has been successfully applied. This can be done by checking the Update History in Windows Settings or by querying the installed KBs via PowerShell:
Get-HotFix -Id KB[Insert_Applicable_KB_Number].
Audit Spooler Status: In environments where printing is not required (e.g., certain application servers), consider disabling the Print Spooler service entirely as a permanent mitigation strategy.
Security Best Practices for Print Spooler Hardening
Beyond patching, security teams should implement defensive layers to protect against future Print Spooler vulnerabilities:
Enforce the Principle of Least Privilege: Disable the Print Spooler service on all systems that do not explicitly require it, especially critical infrastructure like Domain Controllers.
Restricted Driver Installation: Use Group Policy Objects (GPO) to restrict the ability to install print drivers to only authorized administrators. Navigate to Computer Configuration\Administrative Templates\Printers\Point and Print Restrictions and set it to "Enabled."
Memory Protection Mechanisms: Ensure that modern memory protections such as Address Space Layout Randomization (ASLR) and Data Execution Prevention (DEP) are enforced globally via Windows Defender Exploit Guard.
Monitor for Anomalous Activity: Configure SIEM/EDR rules to alert on unusual child processes spawned by spoolsv.exe (e.g., cmd.exe, powershell.exe, or net.exe), which are often indicators of successful exploitation.
Network Segmentation: Isolate print servers in dedicated VLANs and use firewalls to restrict traffic to only necessary printing protocols (e.g., port 445 and 135).
Regular Vulnerability Scanning: Incorporate EPSS (Exploit Prediction Scoring System) data into your patch prioritization. With CVE-2022-41073 ranking in the 83.4th percentile, it should be treated with extreme urgency compared to non-exploited flaws.