CVE-2021-33736
📋 TL;DR
CVE-2021-33736 is a SQL injection vulnerability in Siemens SINEC NMS that allows authenticated attackers with administrative privileges to execute arbitrary commands on the local database. This affects all SINEC NMS versions before V1.0 SP2 Update 1. Attackers can exploit this by sending specially crafted requests to the webserver.
💻 Affected Systems
- Siemens SINEC NMS
📦 What is this software?
Sinec Nms by Siemens
Sinec Nms by Siemens
Sinec Nms by Siemens
Sinec Nms by Siemens
⚠️ Risk & Real-World Impact
Worst Case
Complete compromise of the SINEC NMS system, allowing attackers to execute arbitrary database commands, potentially leading to data theft, system manipulation, or lateral movement to connected industrial control systems.
Likely Case
Privileged authenticated attackers gaining unauthorized database access, potentially extracting sensitive network management data or modifying system configurations.
If Mitigated
Limited impact due to proper network segmentation, strong authentication controls, and monitoring preventing successful exploitation attempts.
🎯 Exploit Status
Exploitation requires authenticated administrative access. SQL injection vulnerabilities are typically straightforward to exploit once identified.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: V1.0 SP2 Update 1 or later
Vendor Advisory: https://cert-portal.siemens.com/productcert/pdf/ssa-163251.pdf
Restart Required: Yes
Instructions:
1. Download SINEC NMS V1.0 SP2 Update 1 or later from Siemens support portal. 2. Backup current configuration and data. 3. Install the update following Siemens documentation. 4. Restart the SINEC NMS service. 5. Verify successful update and functionality.
🔧 Temporary Workarounds
Network Segmentation
allRestrict access to SINEC NMS webserver to only trusted administrative networks
Privilege Reduction
allReview and minimize administrative accounts with access to SINEC NMS
🧯 If You Can't Patch
- Implement strict network access controls to limit SINEC NMS webserver access to only necessary administrative systems
- Deploy web application firewall (WAF) with SQL injection protection rules in front of SINEC NMS
🔍 How to Verify
Check if Vulnerable:
Check SINEC NMS version via web interface or system configuration. Versions before V1.0 SP2 Update 1 are vulnerable.Check Version:
Check via SINEC NMS web interface under System Information or Administration settingsVerify Fix Applied:
Verify SINEC NMS version is V1.0 SP2 Update 1 or later. Test that SQL injection attempts are properly rejected.📡 Detection & Monitoring
Log Indicators:
- Unusual database queries in SINEC NMS logs
- Multiple failed authentication attempts followed by successful administrative login
- Unexpected database schema changes or data modifications
Network Indicators:
- Unusual SQL patterns in HTTP requests to SINEC NMS webserver
- Database connection attempts from non-administrative systems
SIEM Query:
source="sinec_nms" AND (http_request CONTAINS "UNION" OR http_request CONTAINS "SELECT" OR http_request CONTAINS "INSERT" OR http_request CONTAINS "DELETE")