CVE-2025-58125
📋 TL;DR
CVE-2025-58125 is an improper certificate validation vulnerability in the Checkmk Exchange plugin Freebox v6 agent. Attackers in a man-in-the-middle position can intercept and potentially manipulate traffic between the agent and Checkmk server. This affects organizations using the Freebox v6 agent plugin in their Checkmk monitoring infrastructure.
💻 Affected Systems
- Checkmk Exchange plugin Freebox v6 agent
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Attackers could intercept sensitive monitoring data, inject false metrics, or disrupt monitoring operations by impersonating legitimate endpoints.
Likely Case
Monitoring data interception leading to information disclosure about system health, performance metrics, and potentially credentials if transmitted insecurely.
If Mitigated
Limited impact with proper network segmentation and certificate validation controls in place.
🎯 Exploit Status
Requires man-in-the-middle position on network path between agent and Checkmk server
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Check Checkmk Exchange for updated Freebox v6 plugin
Vendor Advisory: https://exchange.checkmk.com/p/freebox-v6
Restart Required: Yes
Instructions:
1. Log into Checkmk server
2. Navigate to Setup > Agents > Windows, Linux, Solaris, AIX
3. Update Freebox v6 agent plugin from Checkmk Exchange
4. Restart affected monitoring services
🔧 Temporary Workarounds
Network Segmentation
allIsolate monitoring traffic to trusted network segments
VPN Tunnel
allRoute monitoring traffic through encrypted VPN tunnels
🧯 If You Can't Patch
- Implement strict network access controls between monitoring agents and server
- Deploy network monitoring to detect man-in-the-middle attacks
🔍 How to Verify
Check if Vulnerable:
Check Freebox v6 agent plugin version in Checkmk interface and compare with latest version on Checkmk ExchangeCheck Version:
Check Checkmk web interface under Setup > Agents for plugin versionVerify Fix Applied:
Verify plugin version is updated and certificate validation is enforced in agent configuration📡 Detection & Monitoring
Log Indicators:
- Certificate validation failures in agent logs
- Unexpected certificate changes in TLS handshakes
Network Indicators:
- Unencrypted monitoring traffic
- Certificate mismatches in TLS sessions
SIEM Query:
source="checkmk" AND ("certificate" OR "TLS" OR "SSL") AND ("failure" OR "error" OR "invalid")