CVE-2021-47833: WifiHotSpot Privilege Escalation Flaw

CVE-2021-47833 Overview

CVE-2021-47833 is an unquoted service path vulnerability affecting WifiHotSpot 1.0.0.0. The vulnerability exists in the WifiHotSpotService.exe service, which uses an unquoted path containing spaces. This allows local attackers to plant malicious executables in strategic locations that will be executed with elevated LocalSystem privileges when the service starts during system startup or reboot.

Critical Impact
Local attackers can achieve privilege escalation to LocalSystem by exploiting the unquoted service path, potentially gaining complete control over the affected system.

Affected Products

WifiHotSpot 1.0.0.0
WifiHotSpotService.exe component

Discovery Timeline

2026-01-16 - CVE CVE-2021-47833 published to NVD
2026-01-16 - Last updated in NVD database

Technical Details for CVE-2021-47833

Vulnerability Analysis

This vulnerability falls under CWE-428 (Unquoted Search Path or Element), a well-known Windows security issue affecting services with paths containing spaces. When a Windows service is registered with a path that contains spaces but is not enclosed in quotation marks, Windows attempts to resolve the path by trying various combinations of the path segments.

For example, if a service path is C:\Program Files\WifiHotSpot\WifiHotSpotService.exe, Windows will attempt to execute in order: C:\Program.exe, then C:\Program Files\WifiHotSpot\WifiHotSpotService.exe. An attacker with write access to C:\ or other intermediate directories can place a malicious executable named Program.exe that will be executed with the service's privileges.

The vulnerability requires local access to the system and the ability to write files to directories in the service path. Once exploited, the attacker gains LocalSystem privileges, the highest privilege level on a Windows system.

Root Cause

The root cause is improper configuration of the Windows service registration. The WifiHotSpotService.exe service path was registered without enclosing quotation marks around the full executable path. This is a common development oversight that occurs when services are installed in directories with spaces in their names (such as Program Files).

Attack Vector

The attack requires local access to the target system. An attacker must:

Identify that the WifiHotSpot service uses an unquoted path
Gain write access to a directory that appears earlier in the path resolution sequence (e.g., C:\ or C:\Program Files\)
Place a malicious executable with a name that Windows will attempt to execute first (e.g., Program.exe)
Wait for or trigger a system restart or service restart
The malicious executable runs with LocalSystem privileges

The exploitation is straightforward and does not require any user interaction beyond the service restart or system reboot. An existing proof-of-concept exploit is publicly available via Exploit-DB #49845.

Detection Methods for CVE-2021-47833

Indicators of Compromise

Unexpected executables named Program.exe or similar in the root drive directory or intermediate path locations
Suspicious files appearing in C:\ or C:\Program Files\ with execution timestamps coinciding with system startup
Process execution events showing Program.exe spawning from unexpected locations with SYSTEM privileges
New or modified files in service path directories that were not part of legitimate software installations

Detection Strategies

Monitor for file creation events in C:\ and other common unquoted path exploitation locations using endpoint detection and response (EDR) tools
Use Windows Security Event Log monitoring for suspicious service execution patterns (Event ID 7045 for new service installations)
Implement file integrity monitoring on directories commonly targeted by unquoted service path attacks
Scan the Windows registry for services with unquoted paths that contain spaces using tools like PowerShell or dedicated vulnerability scanners

Monitoring Recommendations

Enable command-line process auditing to capture the full path of executed processes
Configure SentinelOne Singularity to alert on process creation events from unexpected paths running as SYSTEM
Implement baseline monitoring of startup executables and alert on deviations
Regularly audit Windows services for unquoted path configurations using automated scripts

How to Mitigate CVE-2021-47833

Immediate Actions Required

Audit the WifiHotSpot service registration and add quotation marks around the service path in the Windows registry
Review directory permissions along the service path to restrict write access to administrators only
Scan for any suspicious executables in C:\ and intermediate directories in the service path
Consider disabling or uninstalling WifiHotSpot 1.0.0.0 until a patched version is available

Patch Information

No vendor patch information is currently available in the CVE data. Organizations should contact Gearbox Computers for remediation guidance. Additional information may be available via the VulnCheck Advisory on WiFiHotspotServiceExe or the Gearbox Computers Hotspot Info page.

Workarounds

Manually fix the unquoted service path by modifying the registry key HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\WifiHotSpotService to enclose the ImagePath value in quotation marks
Restrict write permissions on the C:\ drive and C:\Program Files\ directory to prevent unauthorized executable placement
Implement application whitelisting to prevent execution of unauthorized executables from sensitive directories
Use SentinelOne's behavioral AI to detect and block privilege escalation attempts through service path manipulation

bash

# Registry fix example - Enclose service path in quotes
# Run as Administrator in PowerShell
$serviceName = "WifiHotSpotService"
$regPath = "HKLM:\SYSTEM\CurrentControlSet\Services\$serviceName"
$currentPath = (Get-ItemProperty -Path $regPath).ImagePath
# Add quotes if not present
if ($currentPath -notmatch '^".*"$') {
    $quotedPath = '"' + $currentPath + '"'
    Set-ItemProperty -Path $regPath -Name ImagePath -Value $quotedPath
}