CVE-2023-26039
📋 TL;DR
CVE-2023-26039 is an OS command injection vulnerability in ZoneMinder's HostController.php that allows authenticated users to execute arbitrary shell commands as the web server user. This affects all ZoneMinder installations running versions before 1.36.33 or 1.37.33. The vulnerability enables remote code execution through API calls.
💻 Affected Systems
- ZoneMinder
📦 What is this software?
Zoneminder by Zoneminder
Zoneminder by Zoneminder
⚠️ Risk & Real-World Impact
Worst Case
Full system compromise allowing attacker to execute arbitrary commands, install malware, pivot to other systems, and potentially gain root access through privilege escalation.
Likely Case
Attacker gains web server user privileges, accesses camera feeds, modifies configurations, and potentially installs cryptocurrency miners or backdoors.
If Mitigated
Limited impact if proper network segmentation, minimal web user privileges, and strict API access controls are implemented.
🎯 Exploit Status
Exploitation requires authenticated access but is straightforward via crafted API calls. Public exploit code exists in security advisories.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 1.36.33 or 1.37.33
Vendor Advisory: https://github.com/ZoneMinder/zoneminder/security/advisories/GHSA-44q8-h2pw-cc9g
Restart Required: Yes
Instructions:
1. Backup current ZoneMinder configuration and database. 2. Update ZoneMinder to version 1.36.33 or 1.37.33 using your distribution's package manager or from source. 3. Restart the ZoneMinder service and web server (Apache/Nginx). 4. Verify the update was successful.
🔧 Temporary Workarounds
Restrict API Access
linuxLimit access to the vulnerable API endpoint using web server configuration or firewall rules.
# Apache: Add to .htaccess or virtual host config
<Location "/zm/api/app/Controller/HostController.php">
Deny from all
</Location>
# Nginx: Add to server block
location ~* /zm/api/app/Controller/HostController.php {
deny all;
}
Network Segmentation
linuxIsolate ZoneMinder server from internet and restrict internal access to trusted networks only.
# Example iptables rule to restrict access
sudo iptables -A INPUT -p tcp --dport 80 -s TRUSTED_NETWORK -j ACCEPT
sudo iptables -A INPUT -p tcp --dport 443 -s TRUSTED_NETWORK -j ACCEPT
sudo iptables -A INPUT -p tcp --dport 80 -j DROP
sudo iptables -A INPUT -p tcp --dport 443 -j DROP
🧯 If You Can't Patch
- Implement strict network access controls to limit ZoneMinder access to trusted IP addresses only.
- Reduce web server user privileges, implement SELinux/AppArmor profiles, and monitor for suspicious command execution.
🔍 How to Verify
Check if Vulnerable:
Check ZoneMinder version via web interface (Settings -> System) or command line: grep ZM_VERSION /usr/share/zoneminder/includes/version.phpCheck Version:
grep ZM_VERSION /usr/share/zoneminder/includes/version.php | cut -d"'" -f2Verify Fix Applied:
Verify version is 1.36.33 or higher (1.36.x branch) or 1.37.33 or higher (1.37.x branch). Test API endpoint with safe commands to confirm sanitization.📡 Detection & Monitoring
Log Indicators:
- Unusual API calls to HostController.php
- Suspicious shell commands in web server logs
- Multiple failed authentication attempts followed by API access
Network Indicators:
- Unusual outbound connections from ZoneMinder server
- Traffic to command and control servers
- Unexpected port scans originating from ZoneMinder host
SIEM Query:
source="apache" OR source="nginx" AND (uri="/zm/api/app/Controller/HostController.php" AND (method="POST" OR method="PUT")) AND (user_agent NOT CONTAINS "browser" OR user_agent="*")