CVE-2021-36185
📋 TL;DR
This vulnerability allows attackers to execute arbitrary operating system commands on Fortinet FortiWLM systems by sending specially crafted HTTP requests. It affects FortiWLM version 8.6.1 and earlier. Attackers can potentially gain full control of affected systems.
💻 Affected Systems
- Fortinet FortiWLM
📦 What is this software?
Fortiwlm by Fortinet
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise allowing attacker to install persistent backdoors, steal sensitive data, pivot to other network resources, or deploy ransomware.
Likely Case
Unauthorized command execution leading to data exfiltration, service disruption, or lateral movement within the network.
If Mitigated
Limited impact if proper network segmentation and access controls prevent exploitation attempts from reaching vulnerable systems.
🎯 Exploit Status
The vulnerability requires no authentication and exploitation is straightforward once the attack vector is identified.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 8.6.2 or later
Vendor Advisory: https://fortiguard.com/advisory/FG-IR-21-110
Restart Required: Yes
Instructions:
1. Download FortiWLM version 8.6.2 or later from Fortinet support portal. 2. Backup current configuration. 3. Apply the update following Fortinet's upgrade procedures. 4. Restart the system to complete installation.
🔧 Temporary Workarounds
Network Access Restriction
allRestrict HTTP/HTTPS access to FortiWLM management interface to trusted IP addresses only.
Configure firewall rules to allow only specific source IPs to access FortiWLM management ports (typically 80/443)
🧯 If You Can't Patch
- Isolate FortiWLM systems in a separate network segment with strict access controls
- Implement web application firewall (WAF) rules to block OS command injection patterns
🔍 How to Verify
Check if Vulnerable:
Check FortiWLM version via web interface (System > Dashboard) or CLI command 'get system status'Check Version:
get system status | grep VersionVerify Fix Applied:
Verify version is 8.6.2 or higher and test that command injection attempts are blocked📡 Detection & Monitoring
Log Indicators:
- Unusual command execution in system logs
- HTTP requests containing shell metacharacters like ;, |, &, $, `
Network Indicators:
- HTTP requests to FortiWLM with suspicious parameters containing shell commands
SIEM Query:
source="fortiwlm" AND (http_request CONTAINS ";" OR http_request CONTAINS "|" OR http_request CONTAINS "$" OR http_request CONTAINS "`")