CVE-2023-31208
📋 TL;DR
This vulnerability allows authorized users of Checkmk's RestAPI to execute arbitrary livestatus commands due to improper input sanitization. Attackers with valid credentials can potentially execute commands on the underlying system. Affected users include anyone running vulnerable Checkmk versions with RestAPI enabled.
💻 Affected Systems
- Checkmk
📦 What is this software?
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⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise via arbitrary command execution leading to data theft, lateral movement, or ransomware deployment.
Likely Case
Unauthorized data access, configuration changes, or service disruption within the monitoring environment.
If Mitigated
Limited impact if proper network segmentation and least privilege access controls are implemented.
🎯 Exploit Status
Exploitation requires valid authentication to the RestAPI. The vulnerability is in command delimiter handling, making exploitation straightforward for authenticated attackers.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 2.0.0p36, 2.1.0p28, or 2.2.0b8
Vendor Advisory: https://checkmk.com/werk/15191
Restart Required: Yes
Instructions:
1. Backup your Checkmk configuration. 2. Update to the patched version using your package manager (apt/yum) or Checkmk's update mechanism. 3. Restart Checkmk services. 4. Verify the update was successful.
🔧 Temporary Workarounds
Disable RestAPI
linuxTemporarily disable the RestAPI if not required, preventing exploitation.
omd stop [SITE]
Edit site configuration to disable RestAPI
omd start [SITE]
Restrict API Access
linuxLimit RestAPI access to trusted IP addresses using firewall rules.
iptables -A INPUT -p tcp --dport [API_PORT] -s [TRUSTED_IP] -j ACCEPT
iptables -A INPUT -p tcp --dport [API_PORT] -j DROP
🧯 If You Can't Patch
- Implement strict network segmentation to isolate Checkmk from critical systems.
- Enforce least privilege access controls and monitor RestAPI usage for suspicious activity.
🔍 How to Verify
Check if Vulnerable:
Check Checkmk version: if running < 2.0.0p36, < 2.1.0p28, or < 2.2.0b8 and RestAPI is enabled, the system is vulnerable.Check Version:
omd versionVerify Fix Applied:
Verify the version is updated to 2.0.0p36, 2.1.0p28, or 2.2.0b8 or later.📡 Detection & Monitoring
Log Indicators:
- Unusual livestatus command patterns in Checkmk logs
- Multiple failed authentication attempts followed by successful API access
Network Indicators:
- Unexpected outbound connections from Checkmk server
- Unusual API request patterns to RestAPI endpoints
SIEM Query:
source="checkmk.log" AND "livestatus" AND ("command" OR "exec")