CVE-2020-15934
📋 TL;DR
A local privilege escalation vulnerability in FortiClient for Linux allows local users to execute arbitrary code with root privileges by exploiting the VCM engine. This affects FortiClient for Linux versions 6.2.7 and below, and version 6.4.0. Attackers with local access can elevate their privileges to gain full system control.
💻 Affected Systems
- FortiClient for Linux
📦 What is this software?
Forticlient by Fortinet
Forticlient by Fortinet
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise with root access, enabling installation of persistent backdoors, credential theft, lateral movement, and data exfiltration.
Likely Case
Local attackers gaining administrative control over the affected Linux system, allowing them to bypass security controls and access sensitive data.
If Mitigated
Limited impact if proper access controls restrict local user accounts and privilege escalation is monitored.
🎯 Exploit Status
Exploitation requires local access to the system. The vulnerability is in the VCM engine component that runs with elevated privileges.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: FortiClient for Linux 6.4.1 and later, 6.2.8 and later
Vendor Advisory: https://www.fortiguard.com/psirt/FG-IR-20-110
Restart Required: Yes
Instructions:
1. Download FortiClient for Linux version 6.4.1 or later from Fortinet support portal. 2. Uninstall current vulnerable version. 3. Install the patched version. 4. Restart the system to ensure all components are updated.
🔧 Temporary Workarounds
Restrict local user access
linuxLimit local user accounts on systems running FortiClient for Linux to reduce attack surface.
Monitor privilege escalation attempts
linuxImplement monitoring for privilege escalation activities and unauthorized root access attempts.
🧯 If You Can't Patch
- Uninstall FortiClient for Linux from affected systems if not required
- Implement strict access controls and monitor for suspicious local user activity
🔍 How to Verify
Check if Vulnerable:
Check FortiClient version: Run 'forticlient --version' or check installed package version via package manager.Check Version:
forticlient --versionVerify Fix Applied:
Verify installed version is 6.4.1 or later, or 6.2.8 or later. Check that no unauthorized privilege escalation has occurred.📡 Detection & Monitoring
Log Indicators:
- Unexpected privilege escalation events
- Unauthorized root access attempts
- Suspicious process execution from FortiClient components
Network Indicators:
- Outbound connections from FortiClient processes to unexpected destinations
SIEM Query:
source="forticlient" AND (event_type="privilege_escalation" OR user="root")