CVE-2023-46718
📋 TL;DR
This CVE describes a stack-based buffer overflow vulnerability in Fortinet FortiOS that allows attackers to execute arbitrary code or commands via specially crafted CLI commands. The vulnerability affects multiple FortiOS versions across major release branches. Organizations using affected FortiOS versions on their FortiGate devices are at risk.
💻 Affected Systems
- Fortinet FortiOS
📦 What is this software?
Fortios by Fortinet
Fortios by Fortinet
Fortios by Fortinet
Fortios by Fortinet
Fortios by Fortinet
Fortiproxy by Fortinet
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise allowing attacker to gain root privileges, install persistent backdoors, pivot to internal networks, and exfiltrate sensitive data.
Likely Case
Attacker gains administrative access to the FortiGate device, enabling configuration changes, traffic interception, and lateral movement to connected networks.
If Mitigated
Limited impact due to network segmentation, restricted CLI access, and proper authentication controls preventing exploitation.
🎯 Exploit Status
Requires authenticated CLI access. Exploitation involves crafting specific CLI commands to trigger buffer overflow.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: FortiOS 7.4.2, 7.2.8, 7.0.13, 6.4.16, 6.2.17, 6.0.19 and later
Vendor Advisory: https://fortiguard.fortinet.com/psirt/FG-IR-23-354
Restart Required: No
Instructions:
1. Log into FortiGate web interface. 2. Navigate to System > Firmware. 3. Upload and install the patched firmware version. 4. Verify installation and configuration integrity.
🔧 Temporary Workarounds
Restrict CLI Access
allLimit CLI access to trusted administrative accounts and networks only
config system admin
edit <admin_user>
set trusthost1 <trusted_ip>/<mask>
end
Enable CLI Session Logging
allEnable detailed logging of CLI sessions for detection and auditing
config log setting
set cli-audit-log enable
end
🧯 If You Can't Patch
- Implement strict network segmentation to isolate FortiGate management interfaces
- Enforce multi-factor authentication for all administrative accounts
🔍 How to Verify
Check if Vulnerable:
Check FortiOS version via CLI: 'get system status' or web interface: Dashboard > StatusCheck Version:
get system status | grep VersionVerify Fix Applied:
Verify installed version is equal to or higher than patched versions listed in vendor advisory📡 Detection & Monitoring
Log Indicators:
- Unusual CLI command patterns
- Multiple failed CLI authentication attempts
- CLI sessions from unexpected source IPs
Network Indicators:
- Unusual traffic patterns from FortiGate management interfaces
- Anomalous outbound connections from FortiGate
SIEM Query:
source="fortigate" AND (event_type="cli" AND command="*" AND user!="expected_admin")