CVE-2019-25288: Wacom WTabletService Privilege Escalation

CVE-2019-25288 Overview

CVE-2019-25288 is an unquoted service path vulnerability affecting Wacom WTabletService version 6.6.7-3. This security flaw allows local attackers to execute malicious code with elevated privileges by exploiting the improper handling of service executable paths in Windows. When the service path contains spaces and is not properly quoted, Windows may interpret portions of the path as separate arguments, allowing attackers to plant malicious executables that will be executed with SYSTEM privileges when the service restarts or the system reboots.

Critical Impact

Local privilege escalation vulnerability enabling attackers to execute arbitrary code with SYSTEM-level privileges through malicious executable placement in the unquoted service path.

Affected Products

• Wacom WTabletService 6.6.7-3
• Wacom tablet driver installations using vulnerable WTabletService versions
• Windows systems with Wacom drawing tablet software installed

Discovery Timeline

• 2026-02-05 - CVE CVE-2019-25288 published to NVD
• 2026-02-05 - Last updated in NVD database

Technical Details for CVE-2019-25288

Vulnerability Analysis

This vulnerability falls under CWE-428 (Unquoted Search Path or Element), a common Windows privilege escalation technique. The Wacom WTabletService registers its service executable path without proper quotation marks. When Windows services are configured with unquoted paths containing spaces, the Service Control Manager (SCM) attempts to locate the executable by parsing the path at each space character.

For example, if the service path is C:\Program Files\Wacom\WTabletService.exe, Windows will attempt to execute files in this order: C:\Program.exe, C:\Program Files\Wacom\WTabletService.exe. An attacker with write access to C:\ or other directories in the path hierarchy can place a malicious executable named Program.exe which will be executed with the service's privileges (typically SYSTEM) when the service starts.

Root Cause

The root cause is the failure to enclose the service executable path in double quotation marks during service registration. When installing the Wacom WTabletService, the installer does not properly quote the ImagePath registry value under HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\WTabletService. This oversight allows the Windows path parsing behavior to be exploited for privilege escalation.

Attack Vector

The attack requires local access to the target system and sufficient permissions to write files to directories within the unquoted path. An attacker would follow this exploitation path:

1. Identify the unquoted service path using tools like wmic service get name,displayname,pathname,startmode or PowerShell queries
2. Determine a writable directory within the path hierarchy (commonly C:\ if misconfigured permissions exist)
3. Place a malicious executable named to match the truncated path (e.g., Program.exe)
4. Wait for the service to restart or trigger a system reboot
5. The malicious executable runs with SYSTEM privileges before the legitimate service starts

Technical details and proof-of-concept information can be found in the Exploit-DB #47593 advisory and the VulnCheck Advisory.

Detection Methods for CVE-2019-25288

Indicators of Compromise

• Unexpected executable files in root directories such as C:\Program.exe, C:\Program Files.exe, or similar truncated path names
• Unauthorized modifications to the Wacom service configuration or registry keys
• Process execution events showing suspicious executables running under SYSTEM context near service restart times
• File creation events in C:\ or C:\Program Files\ directories by non-administrative users

Detection Strategies

• Query Windows services for unquoted paths containing spaces using wmic service get name,pathname,startmode | findstr /i /v """ to identify vulnerable services
• Monitor registry key HKLM\SYSTEM\CurrentControlSet\Services\WTabletService\ImagePath for unquoted values
• Implement file integrity monitoring (FIM) on directories commonly targeted by unquoted path attacks
• Use endpoint detection rules to alert on executable creation in root directories or service path locations

Monitoring Recommendations

• Deploy SentinelOne behavioral AI to detect privilege escalation attempts through service manipulation
• Enable Windows Event Log monitoring for Service Control Manager events (Event ID 7045) indicating new service installations
• Monitor for process creation events where parent process is services.exe and the child process is located in unexpected directories
• Implement alerting for any executable file creation in C:\ or other root/system directories

How to Mitigate CVE-2019-25288

Immediate Actions Required

• Audit all Windows services on affected systems for unquoted paths using built-in tools or security scanners
• Verify that directory permissions along the service path do not allow unprivileged users to write files
• Update Wacom tablet drivers to the latest version from the official Wacom website
• Manually quote the service path in the registry if an updated driver is not available

Patch Information

Users should obtain updated Wacom drivers from the official Wacom support channels. The vendor may have addressed this vulnerability in newer driver releases. Check the Wacom Official Website for the latest driver downloads and security updates.

Workarounds

• Manually fix the unquoted path by modifying the registry key HKLM\SYSTEM\CurrentControlSet\Services\WTabletService\ImagePath to include proper quotation marks around the executable path
• Restrict write permissions on directories within the service path hierarchy to administrators only
• Implement application whitelisting to prevent unauthorized executables from running in protected directories
• Use Group Policy to enforce proper service path quoting across managed Windows systems

# Configuration example - Fix unquoted service path via registry
# Run as Administrator in Command Prompt:
reg add "HKLM\SYSTEM\CurrentControlSet\Services\WTabletService" /v ImagePath /t REG_EXPAND_SZ /d "\"C:\Program Files\Wacom\WTabletService.exe\"" /f

# Verify the fix:
reg query "HKLM\SYSTEM\CurrentControlSet\Services\WTabletService" /v ImagePath

# PowerShell alternative to identify all unquoted service paths:
Get-WmiObject win32_service | Where-Object {$_.PathName -notlike '"*' -and $_.PathName -like '* *'} | Select-Object Name, PathName