CVE-2024-23811
📋 TL;DR
SINEC NMS versions before V2.0 SP1 contain a vulnerability allowing arbitrary file upload via TFTP. Attackers can upload malicious firmware images or other files, potentially leading to remote code execution. All users running affected SINEC NMS versions are impacted.
💻 Affected Systems
- SINEC NMS
📦 What is this software?
Sinec Nms by Siemens
Sinec Nms by Siemens
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution with full system compromise, allowing attackers to take control of the SINEC NMS server and potentially pivot to other network systems.
Likely Case
Malicious firmware upload leading to service disruption, data theft, or installation of persistent backdoors on the network management system.
If Mitigated
Limited impact with proper network segmentation and access controls, potentially only affecting the SINEC NMS instance itself.
🎯 Exploit Status
TFTP protocol typically requires no authentication, making exploitation straightforward if network access is available.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: V2.0 SP1
Vendor Advisory: https://cert-portal.siemens.com/productcert/html/ssa-943925.html
Restart Required: Yes
Instructions:
1. Download SINEC NMS V2.0 SP1 from Siemens support portal. 2. Backup current configuration and data. 3. Install the update following Siemens documentation. 4. Restart the SINEC NMS service.
🔧 Temporary Workarounds
Disable TFTP Service
linuxDisable the TFTP service if not required for operations
systemctl disable tftpd
systemctl stop tftpd
Network Access Control
linuxRestrict TFTP access to trusted IP addresses only
iptables -A INPUT -p udp --dport 69 -s TRUSTED_IP -j ACCEPT
iptables -A INPUT -p udp --dport 69 -j DROP
🧯 If You Can't Patch
- Isolate SINEC NMS on a dedicated VLAN with strict firewall rules blocking all unnecessary inbound traffic
- Implement network monitoring for TFTP traffic and file upload attempts to the SINEC NMS server
🔍 How to Verify
Check if Vulnerable:
Check SINEC NMS version via web interface or system logs. If version is below V2.0 SP1, system is vulnerable.Check Version:
Check web interface or consult Siemens documentation for version verification commandVerify Fix Applied:
Verify SINEC NMS version shows V2.0 SP1 or higher after update installation.📡 Detection & Monitoring
Log Indicators:
- TFTP file upload logs showing unexpected file types or sizes
- System logs showing unexpected process execution or service restarts
Network Indicators:
- Unexpected TFTP traffic to SINEC NMS server
- Large file transfers via TFTP protocol
SIEM Query:
source_port=69 AND dest_ip=SINEC_NMS_IP AND protocol=udp AND bytes_transferred>1000000