CVE-2018-5781
📋 TL;DR
This vulnerability allows unauthenticated attackers to execute arbitrary PHP code on Mitel conferencing systems by sending specially crafted requests to the vendrecording.php page. Affected systems include Mitel Connect ONSITE R1711-PREM and earlier, and Mitel ST 14.2 GA28 and earlier. Successful exploitation gives attackers full control over the vulnerable system.
💻 Affected Systems
- Mitel Connect ONSITE
- Mitel ST 14.2
📦 What is this software?
St14.2 by Mitel
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise allowing attackers to install backdoors, steal sensitive data, pivot to internal networks, and disrupt business communications.
Likely Case
Remote code execution leading to data theft, installation of cryptocurrency miners, or ransomware deployment.
If Mitigated
Limited impact if systems are isolated, patched, or have web application firewalls blocking malicious requests.
🎯 Exploit Status
Simple HTTP POST requests with PHP code injection can trigger the vulnerability without authentication.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Mitel Connect ONSITE: R1711-PREM SP1 and later; Mitel ST 14.2: GA29 and later
Vendor Advisory: https://www.mitel.com/support/security-advisories/mitel-product-security-advisory-18-0004
Restart Required: Yes
Instructions:
1. Download the latest patch from Mitel support portal. 2. Backup current configuration. 3. Apply the patch following vendor instructions. 4. Restart the application/services. 5. Verify the patch is applied correctly.
🔧 Temporary Workarounds
Block vendrecording.php access
linuxUse web application firewall or network firewall to block access to /vendrecording.php
iptables -A INPUT -p tcp --dport 80 -m string --string "vendrecording.php" --algo bm -j DROP
iptables -A INPUT -p tcp --dport 443 -m string --string "vendrecording.php" --algo bm -j DROP
Restrict network access
linuxLimit access to Mitel systems to trusted IP addresses only
iptables -A INPUT -p tcp --dport 80 -s TRUSTED_IP -j ACCEPT
iptables -A INPUT -p tcp --dport 443 -s TRUSTED_IP -j ACCEPT
iptables -A INPUT -p tcp --dport 80 -j DROP
iptables -A INPUT -p tcp --dport 443 -j DROP
🧯 If You Can't Patch
- Isolate affected systems in separate network segments with strict firewall rules
- Implement web application firewall (WAF) with rules to detect and block PHP injection attempts
🔍 How to Verify
Check if Vulnerable:
Check if system responds to requests to /vendrecording.php with PHP code injection attempts (test in isolated environment only)Check Version:
Check Mitel administration interface or consult vendor documentation for version informationVerify Fix Applied:
Verify version is updated to patched version and test that vendrecording.php no longer accepts malicious input📡 Detection & Monitoring
Log Indicators:
- HTTP POST requests to vendrecording.php with PHP code patterns
- Unusual process execution from web server user
- File creation/modification in web directories
Network Indicators:
- HTTP requests containing '<?php' or 'eval(' patterns to conferencing endpoints
- Outbound connections from Mitel systems to suspicious IPs
SIEM Query:
source="web_logs" AND (uri="/vendrecording.php" AND (body="<?php" OR body="eval(" OR body="system("))