CVE-2022-24459: Windows 10 Privilege Escalation Flaw

CVE-2022-24459 Overview

CVE-2022-24459 is an Elevation of Privilege vulnerability affecting the Windows Fax and Scan Service across a wide range of Microsoft Windows operating systems. This vulnerability allows a local attacker with low privileges to escalate their permissions to gain elevated access on affected systems. The Windows Fax and Scan Service, a built-in Windows component used for sending and receiving faxes and scanning documents, contains a security flaw that can be exploited to compromise system integrity.

Critical Impact

Successful exploitation of this vulnerability enables attackers to elevate privileges locally, potentially gaining complete control over affected Windows systems with full read, write, and execute capabilities.

Affected Products

• Microsoft Windows 10 (all versions including 1607, 1809, 1909, 20H2, 21H1, 21H2)
• Microsoft Windows 11 (x64 and ARM64 architectures)
• Microsoft Windows 7 SP1
• Microsoft Windows 8.1
• Microsoft Windows RT 8.1
• Microsoft Windows Server 2008 SP2, R2 SP1
• Microsoft Windows Server 2012, 2012 R2
• Microsoft Windows Server 2016
• Microsoft Windows Server 2019
• Microsoft Windows Server 2022, 20H2

Discovery Timeline

• March 9, 2022 - CVE-2022-24459 published to NVD
• November 21, 2024 - Last updated in NVD database

Technical Details for CVE-2022-24459

Vulnerability Analysis

This elevation of privilege vulnerability exists within the Windows Fax and Scan Service (WFS.exe). The service, which runs with elevated privileges to perform fax and document scanning operations, contains a security flaw that allows authenticated local users to escalate their privileges. An attacker who successfully exploits this vulnerability could execute code with elevated permissions, enabling them to install programs, view, change, or delete data, or create new accounts with full user rights.

The vulnerability requires local access to the target system and low-privilege authentication, meaning an attacker must first gain a foothold on the system through another means before exploiting this flaw. No user interaction is required for successful exploitation, making it particularly dangerous in environments where users may have legitimate but limited access to Windows systems.

Root Cause

The root cause of CVE-2022-24459 stems from improper handling of permissions or security controls within the Windows Fax and Scan Service. The service fails to properly validate or restrict certain operations, allowing a low-privileged user to perform actions that should be reserved for higher-privileged accounts. This flaw in the privilege management logic creates an opportunity for local attackers to bypass intended security boundaries.

Attack Vector

The attack vector for CVE-2022-24459 is local, meaning an attacker must have physical or remote access to an authenticated session on the vulnerable system. The attack follows this general pattern:

1. The attacker gains initial access to the target Windows system with a low-privileged user account
2. The attacker interacts with the Windows Fax and Scan Service in a manner that triggers the vulnerability
3. The service improperly handles the request, allowing the attacker's code or commands to execute with elevated privileges
4. The attacker gains SYSTEM-level or administrator-equivalent access to the compromised machine

The vulnerability can be exploited with low attack complexity and requires no user interaction, making it a reliable privilege escalation vector for attackers who have already established initial access.

Detection Methods for CVE-2022-24459

Indicators of Compromise

• Unexpected processes spawning from WFS.exe (Windows Fax and Scan Service executable)
• Abnormal privilege escalation events logged in Windows Security Event Log (Event ID 4672, 4688)
• Suspicious modifications to system files or registry keys by non-administrative users
• Unusual service behavior or crashes related to the Fax and Scan Service

Detection Strategies

• Monitor Windows Security Event Logs for privilege escalation indicators, particularly Event ID 4672 (Special privileges assigned to new logon)
• Implement behavioral detection rules to identify processes spawned with elevated privileges from the Fax and Scan Service context
• Deploy endpoint detection and response (EDR) solutions capable of detecting local privilege escalation techniques
• Audit and monitor access to the Windows Fax and Scan Service for unusual patterns

Monitoring Recommendations

• Enable detailed logging for Windows services, particularly focusing on the Fax and Scan Service
• Configure SentinelOne agents to monitor for privilege escalation behaviors and service exploitation patterns
• Implement process monitoring to detect abnormal parent-child process relationships involving WFS.exe
• Review Windows Event Logs regularly for signs of exploitation attempts

How to Mitigate CVE-2022-24459

Immediate Actions Required

• Apply Microsoft's security updates for CVE-2022-24459 immediately on all affected Windows systems
• If the Windows Fax and Scan Service is not required, consider disabling it to reduce attack surface
• Implement network segmentation to limit lateral movement in case of compromise
• Ensure SentinelOne endpoint protection is deployed and configured to detect privilege escalation attempts

Patch Information

Microsoft has released security updates to address CVE-2022-24459. Organizations should apply the appropriate patches based on their Windows version. The official security guidance and patch information is available through the Microsoft Security Update Guide for CVE-2022-24459.

Administrators should prioritize patching systems where the Fax and Scan Service is actively used or enabled. For systems where the service is not needed, disabling it provides an additional layer of protection until patches can be applied.

Workarounds

• Disable the Windows Fax and Scan Service on systems where fax and scanning functionality is not required using Services management console (services.msc)
• Restrict physical and remote access to affected systems to trusted users only
• Implement the principle of least privilege to minimize the impact of potential exploitation
• Deploy application control policies to prevent unauthorized code execution

# Disable Windows Fax and Scan Service via PowerShell
Stop-Service -Name "WFS" -Force
Set-Service -Name "WFS" -StartupType Disabled

# Verify service is disabled
Get-Service -Name "WFS" | Select-Object Name, Status, StartType