CVE-2019-25309: Zilab Remote Console Privilege Escalation

CVE-2019-25309 Overview

CVE-2019-25309 is an unquoted service path vulnerability affecting Zilab Remote Console Server version 3.2.9. This flaw allows local attackers to potentially execute arbitrary code with elevated system privileges by exploiting the unquoted binary path in the Windows service configuration. When the service starts, Windows may incorrectly parse the path and execute a malicious executable planted by an attacker, granting LocalSystem permissions.

Critical Impact

Local attackers can achieve privilege escalation to LocalSystem by placing malicious executables in strategic locations along the unquoted service path, potentially gaining full control of the affected system.

Affected Products

• Zilab Remote Console Server 3.2.9

Discovery Timeline

• 2026-02-11 - CVE CVE-2019-25309 published to NVD
• 2026-02-11 - Last updated in NVD database

Technical Details for CVE-2019-25309

Vulnerability Analysis

This vulnerability stems from CWE-428 (Unquoted Search Path or Element), a classic Windows privilege escalation vector. When a Windows service is configured with an executable path containing spaces that is not enclosed in quotation marks, the Windows 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\Zilab\Remote Console Server\service.exe, Windows will attempt to execute in the following order:

1. C:\Program.exe
2. C:\Program Files\Zilab\Remote.exe
3. C:\Program Files\Zilab\Remote Console\Server\service.exe

If an attacker can write to any of these intermediate locations (such as C:\Program.exe if permissions allow), their malicious executable will be run with the privileges of the service—in this case, LocalSystem privileges.

Root Cause

The root cause is improper configuration of the Windows service binary path during installation. The Zilab Remote Console Server installer fails to enclose the service executable path in quotation marks when registering the service with the Windows Service Control Manager. This oversight creates an exploitable condition when the installation path contains spaces, which is common for software installed in the default C:\Program Files\ directory.

Attack Vector

This is a local attack vector requiring the attacker to have local access to the target system with write permissions to one of the intermediate path locations. The attack typically proceeds as follows:

1. The attacker identifies the vulnerable unquoted service path using tools like wmic service get name,pathname or PowerShell queries
2. The attacker determines which intermediate paths are writable with their current privileges
3. A malicious executable is placed in a writable location along the path (e.g., C:\Program Files\Zilab\Remote.exe)
4. When the service restarts (either manually, through a system reboot, or by triggering a service failure), Windows executes the malicious binary with LocalSystem privileges
5. The attacker gains elevated access and can perform any action on the system

Technical details and proof-of-concept information can be found in the Exploit-DB entry #47506 and the VulnCheck Advisory.

Detection Methods for CVE-2019-25309

Indicators of Compromise

• Unexpected executable files in C:\Program.exe or C:\Program Files\Zilab\Remote.exe locations
• Modified timestamps on files in the Zilab installation directory or parent directories
• Suspicious service-related events in Windows Event Logs around service start times
• Newly created executables in directories along the unquoted service path

Detection Strategies

• Run wmic service get name,pathname,startmode | findstr /i /v """ to identify all services with unquoted paths on the system
• Monitor file system changes in directories that could be exploited by unquoted path vulnerabilities (e.g., C:\, C:\Program Files\)
• Use SentinelOne's behavioral AI to detect anomalous process execution originating from service contexts
• Implement file integrity monitoring on critical system directories

Monitoring Recommendations

• Enable Windows Event Log auditing for service start events (Event ID 7036) and process creation (Event ID 4688)
• Configure alerts for executable file creation in root directories and common exploitation paths
• Deploy endpoint detection and response (EDR) solutions to monitor for privilege escalation attempts
• Review services running with LocalSystem or elevated privileges on a regular basis

How to Mitigate CVE-2019-25309

Immediate Actions Required

• Audit all Windows services for unquoted paths using wmic service get name,pathname,startmode
• Manually correct the service path by enclosing it in quotation marks using the registry or sc config command
• Restrict write permissions on directories in the unquoted path to administrators only
• Monitor for any suspicious executable files that may have been placed in exploitation paths

Patch Information

No official vendor patch has been identified in the available data. Organizations should apply the manual mitigation steps below to address this vulnerability. Consider contacting Zilab or reviewing the Tucows Software Preview for any available updates.

Workarounds

• Manually quote the service path in the Windows Registry at HKLM\SYSTEM\CurrentControlSet\Services\[ServiceName]\ImagePath
• Use the sc config command to update the service binary path with proper quotation marks
• Implement strict NTFS permissions on C:\Program Files\ and its subdirectories to prevent unauthorized write access
• Consider uninstalling Zilab Remote Console Server if it is no longer required or supported

# Configuration example - Fix unquoted service path via command line
sc config "ZilabRemoteConsoleServer" binpath= "\"C:\Program Files\Zilab\Remote Console Server\service.exe\""

# Verify the fix was applied correctly
sc qc "ZilabRemoteConsoleServer"