CVE-2020-36933: HTC IPTInstaller Privilege Escalation

CVE-2020-36933 Overview

HTC IPTInstaller 4.0.9 contains an unquoted service path vulnerability (CWE-428) in the PassThru Service configuration. This flaw allows local attackers to exploit the unquoted binary path to inject and execute malicious code with elevated LocalSystem privileges, potentially leading to complete system compromise.

Critical Impact
Local attackers with basic user privileges can exploit this unquoted service path to achieve LocalSystem-level code execution, enabling full system takeover.

Affected Products

HTC IPTInstaller 4.0.9
HTC PassThru Service

Discovery Timeline

2026-01-25 - CVE-2020-36933 published to NVD
2026-01-26 - Last updated in NVD database

Technical Details for CVE-2020-36933

Vulnerability Analysis

The vulnerability exists within HTC IPTInstaller version 4.0.9, specifically in how the PassThru Service binary path is configured in the Windows registry. When Windows services are registered with paths containing spaces but without proper quotation marks, the operating system's path resolution mechanism can be manipulated by attackers.

Windows attempts to locate executables by parsing the path at each space character. For example, a path like C:\Program Files\HTC\IPT Installer\Service.exe would cause Windows to attempt execution of C:\Program.exe, then C:\Program Files\HTC\IPT.exe, before finally reaching the intended binary. By placing a malicious executable at one of these intermediate path locations, an attacker can hijack service execution.

Since the PassThru Service runs with LocalSystem privileges, successful exploitation grants the attacker the highest level of system access available in Windows, enabling complete control over the compromised machine.

Root Cause

The root cause is improper service registration where the ImagePath registry value for the PassThru Service lacks quotation marks around a path containing spaces. This is classified as CWE-428 (Unquoted Search Path or Element). The service installation routine failed to properly escape or quote the binary path, creating an exploitable condition that persists across system reboots.

Attack Vector

This is a local privilege escalation attack. An attacker requires initial local access to the system with sufficient permissions to write an executable to a location in the unquoted path hierarchy, typically C:\Program.exe or similar intermediate paths. Once the malicious binary is placed, the attacker can trigger service restart or wait for system reboot to achieve code execution as LocalSystem.

The attack complexity is low as the technique is well-documented and requires no specialized tools. Standard Windows utilities such as sc query and registry inspection tools can identify vulnerable services.

Detection Methods for CVE-2020-36933

Indicators of Compromise

Unexpected executables named Program.exe or similar in root directories or partial path locations
Newly created executables in C:\Program Files\HTC\ with names matching path segments before spaces
Service execution anomalies where the PassThru Service spawns unexpected child processes

Detection Strategies

Query Windows services for unquoted paths using PowerShell: Get-WmiObject win32_service | Where-Object {$_.PathName -notlike '"*"' -and $_.PathName -like '* *'}
Monitor file creation events in root directories and common unquoted path locations
Use SentinelOne's behavioral detection to identify service-based privilege escalation attempts

Monitoring Recommendations

Enable Windows Event logging for service configuration changes (Event ID 7040)
Monitor process creation events where parent process is a Windows service and the child process path differs from the expected service binary
Implement file integrity monitoring on directories commonly targeted by unquoted service path exploits

How to Mitigate CVE-2020-36933

Immediate Actions Required

Audit all installed services for unquoted paths containing spaces
Manually correct the PassThru Service ImagePath registry value by adding quotation marks around the full path
Remove any suspicious executables found in potential exploitation paths

Patch Information

HTC has not released an official patch for this vulnerability as of the last NVD update. System administrators should implement manual registry corrections or consider removing the affected software if it is not required. Refer to the VulnCheck Advisory for IPTInstaller for additional technical details.

Additional reference information is available at:

Workarounds

Manually quote the service path in the Windows registry at HKLM\SYSTEM\CurrentControlSet\Services\[ServiceName]\ImagePath
Restrict write permissions on directories that fall within the unquoted path resolution sequence
Consider uninstalling HTC IPTInstaller if it is not essential for operations
Deploy application whitelisting to prevent unauthorized executables from running regardless of path exploitation

bash

# Registry fix command (run as Administrator)
reg add "HKLM\SYSTEM\CurrentControlSet\Services\PassThruService" /v ImagePath /t REG_EXPAND_SZ /d "\"C:\Program Files\HTC\IPT Installer\PassThru.exe\"" /f