CVE-2022-35793: Windows 10 Privilege Escalation Flaw

CVE-2022-35793 Overview

CVE-2022-35793 is a Windows Print Spooler Elevation of Privilege vulnerability affecting a wide range of Microsoft Windows operating systems. The Windows Print Spooler service, which manages print jobs and printer communications, contains a flaw that allows a local attacker with low privileges to escalate their permissions to a higher level. This vulnerability is particularly concerning due to the ubiquitous nature of the Print Spooler service across Windows environments and its history as a target for attackers following the PrintNightmare vulnerability series.

Critical Impact

A successful exploit could allow an authenticated attacker to gain elevated privileges on the affected system, potentially leading to complete system compromise with high impacts on confidentiality, integrity, and availability.

Affected Products

• Microsoft Windows 10 (all versions including 20H2, 21H1, 21H2, 1607, 1809)
• Microsoft Windows 11 (arm64, x64)
• Microsoft Windows 7 SP1
• Microsoft Windows 8.1
• Microsoft Windows RT 8.1
• Microsoft Windows Server 2008 SP2 and R2 SP1
• Microsoft Windows Server 2012 and R2
• Microsoft Windows Server 2016 (including 20H2)
• Microsoft Windows Server 2019
• Microsoft Windows Server 2022

Discovery Timeline

• August 9, 2022 - CVE-2022-35793 published to NVD
• November 21, 2024 - Last updated in NVD database

Technical Details for CVE-2022-35793

Vulnerability Analysis

This vulnerability resides in the Windows Print Spooler service (spoolsv.exe), a critical system component responsible for managing the printing process in Windows environments. The Print Spooler service has been a recurring target for security researchers due to its elevated privileges and complex interactions with the operating system.

The vulnerability requires local access to the system and user interaction, meaning an attacker must first gain a foothold on the target machine and then convince a user to perform a specific action. Once exploited, the attacker can elevate their privileges from a low-privileged user to potentially SYSTEM-level access, enabling full control over the affected machine.

The high impact on confidentiality, integrity, and availability indicates that successful exploitation could allow attackers to read sensitive data, modify system configurations, and disrupt normal operations.

Root Cause

The root cause of this vulnerability stems from improper privilege handling within the Print Spooler service. The CWE classification indicates insufficient information is publicly available about the specific technical flaw, but based on the vulnerability class and historical Print Spooler issues, this likely involves improper validation of user-supplied input or insufficient access controls when processing print-related operations.

The Print Spooler service operates with SYSTEM privileges, and any flaw that allows a lower-privileged user to manipulate the service's behavior can result in privilege escalation. This is consistent with previous Print Spooler vulnerabilities that exploited similar architectural weaknesses.

Attack Vector

The attack vector is local, requiring the attacker to have authenticated access to the vulnerable system. The exploitation also requires user interaction, which adds complexity to successful attacks but does not eliminate the risk. An attacker could potentially combine this vulnerability with social engineering techniques to achieve the required user interaction.

Exploitation scenarios may include:

• A malicious insider with limited privileges seeking to gain administrative access
• An attacker who has compromised a low-privileged account via phishing or credential theft
• Malware that attempts to elevate privileges after initial infection

For technical details on the exploitation mechanism, refer to the Microsoft Security Advisory CVE-2022-35793.

Detection Methods for CVE-2022-35793

Indicators of Compromise

• Unusual activity or crashes involving the spoolsv.exe process
• Unexpected privilege elevation events in Windows Security Event logs (Event ID 4672, 4673)
• Suspicious modifications to Print Spooler-related registry keys under HKLM\SYSTEM\CurrentControlSet\Control\Print
• Creation of unauthorized printer ports or drivers

Detection Strategies

• Monitor Windows Security Event logs for privilege escalation attempts associated with the Print Spooler service
• Deploy endpoint detection and response (EDR) solutions to identify suspicious spoolsv.exe behavior
• Implement file integrity monitoring on Print Spooler configuration files and directories
• Use SentinelOne's behavioral AI to detect anomalous process activity indicative of privilege escalation attempts

Monitoring Recommendations

• Configure audit policies to log detailed Print Spooler service activity
• Enable PowerShell script block logging to detect enumeration or exploitation attempts
• Monitor for new DLL files being loaded by the Print Spooler service
• Implement network segmentation to limit lateral movement if a system is compromised

How to Mitigate CVE-2022-35793

Immediate Actions Required

• Apply the security updates from Microsoft's August 2022 Patch Tuesday release immediately
• Assess all Windows systems in the environment to determine exposure and prioritize patching
• Consider disabling the Print Spooler service on systems that do not require printing functionality
• Review and restrict network access to printing-related ports and services

Patch Information

Microsoft has released security updates to address this vulnerability as part of the August 2022 security updates. Organizations should apply the appropriate updates for their Windows versions as documented in the Microsoft Security Advisory CVE-2022-35793. Use Windows Update, Windows Server Update Services (WSUS), or Microsoft Update Catalog to obtain and deploy the patches.

Workarounds

• Disable the Print Spooler service on systems where printing is not required, especially on domain controllers and servers
• Use Group Policy to restrict the Print Spooler service: Computer Configuration > Administrative Templates > Printers
• Implement the principle of least privilege to limit the impact of potential exploitation
• Consider using Point and Print restrictions to prevent unauthorized printer driver installation

# Disable Print Spooler service on systems that don't require printing
Stop-Service -Name Spooler -Force
Set-Service -Name Spooler -StartupType Disabled

# Verify the service is disabled
Get-Service -Name Spooler | Select-Object Name, Status, StartType