CVE-2019-17658
📋 TL;DR
This CVE describes an unquoted service path vulnerability in FortiClient's FortiTray component on Windows. Attackers can exploit this to gain elevated privileges by placing malicious executables in the service path. Affects FortiClientWindows v6.2.2 and earlier versions.
💻 Affected Systems
- FortiClient Windows
📦 What is this software?
Forticlient by Fortinet
Forticlient by Fortinet
⚠️ Risk & Real-World Impact
Worst Case
Full system compromise with administrative privileges, allowing attackers to install malware, steal credentials, and maintain persistent access.
Likely Case
Local privilege escalation leading to unauthorized administrative access on affected Windows systems.
If Mitigated
Limited impact with proper access controls and monitoring in place, though privilege escalation risk remains.
🎯 Exploit Status
Exploitation requires local access to the system. The vulnerability is well-documented and relatively easy to exploit.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: FortiClient v6.2.3 and later
Vendor Advisory: https://fortiguard.com/advisory/FG-IR-19-281
Restart Required: Yes
Instructions:
1. Download FortiClient v6.2.3 or later from Fortinet support portal. 2. Uninstall current vulnerable version. 3. Install updated version. 4. Restart system.
🔧 Temporary Workarounds
Restrict Write Permissions
windowsModify permissions on the FortiClient installation directory to prevent unauthorized file creation
icacls "C:\Program Files\Fortinet\FortiClient" /deny Users:(OI)(CI)W
Disable FortiTray Service
windowsTemporarily disable the vulnerable FortiTray service
sc config FortiTray start= disabled
sc stop FortiTray
🧯 If You Can't Patch
- Implement strict access controls to prevent unauthorized local access to affected systems
- Monitor for suspicious file creation in FortiClient directories and privilege escalation attempts
🔍 How to Verify
Check if Vulnerable:
Check FortiClient version via GUI or registry: HKEY_LOCAL_MACHINE\SOFTWARE\Fortinet\FortiClient\VersionCheck Version:
reg query "HKLM\SOFTWARE\Fortinet\FortiClient" /v VersionVerify Fix Applied:
Verify version is 6.2.3 or higher and check service path is properly quoted in registry: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\FortiTray📡 Detection & Monitoring
Log Indicators:
- Unexpected file creation in FortiClient directories
- FortiTray service restart events
- Privilege escalation attempts
Network Indicators:
- None - local vulnerability only
SIEM Query:
EventID=4688 AND (ProcessName LIKE '%FortiClient%' OR CommandLine LIKE '%FortiTray%') AND NewProcessName LIKE '%cmd.exe%' OR '%powershell.exe%'