CVE-2021-3193
📋 TL;DR
CVE-2021-3193 is a critical remote code execution vulnerability in Nagios Docker Config Wizard that allows unauthenticated attackers to execute arbitrary commands as the apache user. This affects Nagios XI installations through version 5.7 that have the Docker Config Wizard component. Attackers can gain initial access to vulnerable systems without any authentication.
💻 Affected Systems
- Nagios XI
- Nagios Docker Config Wizard
📦 What is this software?
Nagios Xi by Nagios
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise leading to data theft, lateral movement, ransomware deployment, and persistent backdoor installation across the network.
Likely Case
Initial foothold leading to privilege escalation, credential harvesting, and deployment of cryptocurrency miners or botnet malware.
If Mitigated
Limited to apache user privileges, potentially allowing file system access and further exploitation attempts.
🎯 Exploit Status
Multiple public exploits available, trivial to weaponize due to unauthenticated nature.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Docker Config Wizard 1.1.2 or later, Nagios XI 5.8 or later
Vendor Advisory: https://www.nagios.com/products/security/
Restart Required: Yes
Instructions:
1. Update Nagios XI to version 5.8 or later. 2. Update Docker Config Wizard component to version 1.1.2 or later. 3. Restart Nagios services.
🔧 Temporary Workarounds
Disable Docker Config Wizard
linuxRemove or disable the vulnerable Docker Config Wizard component
rm -rf /usr/local/nagiosxi/html/includes/components/dockerwizard/
systemctl restart nagios
Network Access Control
linuxRestrict access to Nagios web interface using firewall rules
iptables -A INPUT -p tcp --dport 80 -s trusted_network -j ACCEPT
iptables -A INPUT -p tcp --dport 443 -s trusted_network -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
- Immediately isolate vulnerable systems from internet and restrict internal network access
- Implement web application firewall (WAF) rules to block exploitation attempts
🔍 How to Verify
Check if Vulnerable:
Check Nagios XI version: cat /usr/local/nagiosxi/var/xiversion. Check Docker Config Wizard: ls -la /usr/local/nagiosxi/html/includes/components/dockerwizard/Check Version:
cat /usr/local/nagiosxi/var/xiversion && grep 'version' /usr/local/nagiosxi/html/includes/components/dockerwizard/component.inc.phpVerify Fix Applied:
Verify Nagios XI version >= 5.8 and Docker Config Wizard version >= 1.1.2. Test web interface functionality.📡 Detection & Monitoring
Log Indicators:
- Unusual POST requests to /nagiosxi/includes/components/dockerwizard/
- Apache error logs showing command execution attempts
- Sudden apache user process creation
Network Indicators:
- Unusual outbound connections from Nagios server
- Exploit tool traffic patterns to Nagios web interface
SIEM Query:
source="apache" AND (uri="/nagiosxi/includes/components/dockerwizard/*" OR uri="/includes/components/dockerwizard/*") AND (method="POST" OR status>=400)