CVE-2023-36634
📋 TL;DR
This vulnerability in FortiAP-U's command line interpreter allows authenticated attackers to bypass file path filtering and delete or list arbitrary files and directories. It affects FortiAP-U devices running specific firmware versions. Attackers need valid credentials to exploit this vulnerability.
💻 Affected Systems
- FortiAP-U
📦 What is this software?
Fortiap U by Fortinet
Fortiap U by Fortinet
Fortiap U by Fortinet
Fortiap U by Fortinet
⚠️ Risk & Real-World Impact
Worst Case
An attacker could delete critical system files, configuration files, or log files, potentially causing denial of service, data loss, or system compromise.
Likely Case
Attackers with valid credentials could delete or list sensitive files, potentially accessing configuration data or removing evidence of their activities.
If Mitigated
With proper access controls and monitoring, impact is limited to authorized users who might misuse their legitimate access.
🎯 Exploit Status
Exploitation requires authenticated access to the command line interface. The vulnerability is in argument filtering, making exploitation straightforward once authenticated.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 7.0.1, 6.2.6, and later versions
Vendor Advisory: https://fortiguard.com/psirt/FG-IR-23-123
Restart Required: Yes
Instructions:
1. Download the patched firmware from Fortinet support portal. 2. Backup current configuration. 3. Upload and install the new firmware via web interface or CLI. 4. Reboot the device. 5. Verify the firmware version after reboot.
🔧 Temporary Workarounds
Restrict CLI Access
allLimit command line interface access to only necessary administrative users and implement strong authentication controls.
Implement File Integrity Monitoring
allMonitor critical system files for unauthorized changes or deletions to detect exploitation attempts.
🧯 If You Can't Patch
- Implement strict access controls and monitor all CLI sessions for suspicious file operations
- Isolate vulnerable devices from critical network segments and implement network segmentation
🔍 How to Verify
Check if Vulnerable:
Check the firmware version via CLI: 'get system status' or web interface System Information pageCheck Version:
get system status | grep VersionVerify Fix Applied:
Verify firmware version is 7.0.1 or higher, 6.2.6 or higher, or any version not in the affected range📡 Detection & Monitoring
Log Indicators:
- Unusual file deletion or listing commands in CLI logs
- Multiple failed authentication attempts followed by successful login and file operations
Network Indicators:
- Unusual SSH or CLI connections to FortiAP-U devices
- Traffic patterns indicating file exfiltration
SIEM Query:
source="fortiap" AND (command="rm" OR command="ls" OR command="dir") AND (path="*../*" OR path="*/*/*")