CVE-2021-47867: WIN-PACK PRO Privilege Escalation Flaw

CVE-2021-47867 Overview

CVE-2021-47867 is an unquoted service path vulnerability affecting WIN-PACK PRO4.8, specifically in the ScheduleService component. This security flaw allows local users to potentially execute arbitrary code with elevated system privileges by exploiting the improperly quoted service path in C:\Program Files (x86)\WINPAKPRO\ScheduleService Service.exe.

When Windows services are configured with paths containing spaces that are not enclosed in quotation marks, the operating system attempts to interpret the path in an ambiguous manner. An attacker with local access can place a malicious executable at an intermediate path location (such as C:\Program.exe or C:\Program Files (x86)\WINPAKPRO\ScheduleService.exe) that would be executed instead of the legitimate service binary when the service starts or restarts.

Critical Impact

Local privilege escalation to SYSTEM-level access through malicious executable injection during service startup

Affected Products

• WIN-PACK PRO4.8
• Honeywell Win-Pak ScheduleService component

Discovery Timeline

• 2026-01-21 - CVE CVE-2021-47867 published to NVD
• 2026-01-21 - Last updated in NVD database

Technical Details for CVE-2021-47867

Vulnerability Analysis

This vulnerability is classified under CWE-428 (Unquoted Search Path or Element), a well-known Windows security weakness that occurs when executable paths containing spaces are not properly enclosed in quotation marks. The vulnerability specifically affects the ScheduleService component of WIN-PACK PRO4.8, an access control system software.

The attack requires local access to the target system, meaning an attacker must already have some level of access to the machine running WIN-PACK PRO4.8. However, the impact is significant because successful exploitation results in code execution with SYSTEM privileges—the highest privilege level on Windows systems.

Root Cause

The root cause of this vulnerability lies in the improper configuration of the Windows service path for ScheduleService. When the service was registered, the executable path C:\Program Files (x86)\WINPAKPRO\ScheduleService Service.exe was not enclosed in quotation marks.

Windows' CreateProcess function, when parsing an unquoted path with spaces, attempts multiple interpretations:

1. First tries C:\Program.exe
2. Then tries C:\Program Files.exe
3. Then tries C:\Program Files (x86)\WINPAKPRO\ScheduleService.exe
4. Finally resolves to the correct path

This behavior creates multiple opportunities for an attacker to place a malicious executable that Windows will execute before reaching the legitimate service binary.

Attack Vector

The attack vector is local, requiring the attacker to have initial access to the vulnerable system. The exploitation process involves:

1. Reconnaissance: Identifying the unquoted service path using tools like wmic service get name,displayname,pathname,startmode or by querying the Windows registry
2. Write Access Verification: Confirming write permissions to one of the intermediate path locations
3. Payload Deployment: Placing a malicious executable (named appropriately, such as Program.exe or ScheduleService.exe) in a location that Windows will attempt before the legitimate path
4. Trigger Execution: Waiting for or forcing a service restart (system reboot, service failure, or manual restart)

Upon service startup, Windows executes the malicious payload with SYSTEM privileges before reaching the intended service executable.

For technical exploitation details, refer to the Exploit-DB #49691 entry and the VulnCheck Advisory.

Detection Methods for CVE-2021-47867

Indicators of Compromise

• Presence of unexpected executables named Program.exe, ScheduleService.exe, or similar at C:\, C:\Program Files (x86)\, or C:\Program Files (x86)\WINPAKPRO\
• Unusual process execution originating from service startup with SYSTEM privileges
• Registry modifications to service configurations related to WIN-PACK PRO components
• Unexpected child processes spawned by ScheduleService

Detection Strategies

• Run PowerShell or WMIC queries to enumerate all services with unquoted paths containing spaces: wmic service get name,pathname | findstr /i "Program Files"
• Monitor Windows Event Logs for service startup failures or unexpected service-related errors (Event IDs 7000, 7009, 7034)
• Deploy endpoint detection rules to alert on executable creation in path hijacking locations (C:\Program.exe, C:\Program Files.exe, etc.)
• Use file integrity monitoring on critical system directories

Monitoring Recommendations

• Implement continuous monitoring of service binary paths for unauthorized modifications
• Configure alerts for new executable files created in C:\ or C:\Program Files (x86)\WINPAKPRO\ directories
• Monitor process creation events where the parent process is services.exe and the child is in an unusual location
• Review service configurations during regular security audits for unquoted path vulnerabilities

How to Mitigate CVE-2021-47867

Immediate Actions Required

• Audit the WIN-PACK PRO4.8 installation for the unquoted service path vulnerability
• Correct the service path by enclosing it in quotation marks via the Windows Registry or using the sc config command
• Review file system permissions on directories along the service path to restrict write access
• Scan for and remove any suspicious executables in potential hijack locations

Patch Information

Consult the Honeywell Product Repository for official security updates and patched versions of WIN-PACK PRO. Organizations should prioritize upgrading to a version where the service path is properly quoted during installation.

Contact Honeywell support for guidance on the latest secure version of WIN-PACK PRO that addresses this vulnerability.

Workarounds

• Manually fix the unquoted path by modifying the registry key at HKLM\SYSTEM\CurrentControlSet\Services\ScheduleService to include quotation marks around the ImagePath value
• Restrict write permissions on C:\ and C:\Program Files (x86)\WINPAKPRO\ directories to administrators only
• Implement application whitelisting to prevent unauthorized executables from running
• Use SentinelOne's endpoint protection to detect and block malicious executable placement and privilege escalation attempts

# Fix unquoted service path via registry (run as Administrator)
reg add "HKLM\SYSTEM\CurrentControlSet\Services\ScheduleService" /v ImagePath /t REG_EXPAND_SZ /d "\"C:\Program Files (x86)\WINPAKPRO\ScheduleService Service.exe\"" /f