CVE-2022-26648
📋 TL;DR
This vulnerability affects multiple Siemens SCALANCE industrial network switches. An unauthenticated remote attacker can send specially crafted HTTP requests with a malformed XNo parameter to crash affected devices, causing denial of service. All devices running firmware versions below V5.5.2 (for IRT models) or V5.2.6 (for non-IRT models) are vulnerable.
💻 Affected Systems
- SCALANCE X200-4P IRT
- SCALANCE X201-3P IRT
- SCALANCE X201-3P IRT PRO
- SCALANCE X202-2IRT
- SCALANCE X202-2P IRT
- SCALANCE X202-2P IRT PRO
- SCALANCE X204-2
- SCALANCE X204-2FM
- SCALANCE X204-2LD
- SCALANCE X204-2LD TS
- SCALANCE X204-2TS
- SCALANCE X204IRT
- SCALANCE X204IRT PRO
- SCALANCE X206-1
- SCALANCE X206-1LD
- SCALANCE X208
- SCALANCE X208PRO
- SCALANCE X212-2
- SCALANCE X212-2LD
- SCALANCE X216
- SCALANCE X224
- SCALANCE XF201-3P IRT
- SCALANCE XF202-2P IRT
- SCALANCE XF204
- SCALANCE XF204-2
- SCALANCE XF204-2BA IRT
- SCALANCE XF204IRT
- SCALANCE XF206-1
- SCALANCE XF208
📦 What is this software?
Scalance X201 3p Irt Pro Firmware by Siemens
Scalance X202 2p Irt Pro Firmware by Siemens
Scalance Xf204 2ba Irt Firmware by Siemens
⚠️ Risk & Real-World Impact
Worst Case
Complete device crash requiring physical reboot, disrupting industrial network operations and potentially causing production downtime in critical infrastructure environments.
Likely Case
Denial of service affecting network connectivity for connected industrial devices, requiring manual intervention to restore service.
If Mitigated
No impact if devices are patched or properly segmented from untrusted networks.
🎯 Exploit Status
The vulnerability requires sending a malformed HTTP GET request with specific parameter manipulation, which is relatively simple to craft.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: V5.5.2 for IRT models, V5.2.6 for non-IRT models
Vendor Advisory: https://cert-portal.siemens.com/productcert/pdf/ssa-310038.pdf
Restart Required: Yes
Instructions:
1. Download firmware update from Siemens Industrial Security website. 2. Backup device configuration. 3. Upload firmware via web interface or TIA Portal. 4. Apply update and restart device. 5. Verify firmware version after reboot.
🔧 Temporary Workarounds
Network Segmentation
allRestrict access to SCALANCE web management interface to trusted networks only.
Configure firewall rules to block HTTP/HTTPS access from untrusted networks
Implement VLAN segmentation for management interfaces
Disable Web Interface
allDisable HTTP/HTTPS management interface if not required for operations.
Use CLI or TIA Portal to disable web server functionality
🧯 If You Can't Patch
- Implement strict network access controls to limit exposure to management interfaces
- Monitor for unusual HTTP requests to device management interfaces
- Consider physical isolation of affected devices in critical networks
🔍 How to Verify
Check if Vulnerable:
Check firmware version via web interface (System > Device Information) or CLI (show version). Compare against patched versions.Check Version:
show version (CLI) or check System > Device Information in web interfaceVerify Fix Applied:
Confirm firmware version is V5.5.2 or higher for IRT models, or V5.2.6 or higher for non-IRT models. Test HTTP requests with malformed XNo parameter should no longer crash device.📡 Detection & Monitoring
Log Indicators:
- Multiple HTTP requests with malformed XNo parameter
- Device reboot events without scheduled maintenance
- Web interface becoming unresponsive
Network Indicators:
- HTTP GET requests with unusual XNo parameter values to port 80/443
- Sudden loss of connectivity to device management interface
SIEM Query:
source_ip="*" AND dest_port IN (80, 443) AND http_method="GET" AND url_query CONTAINS "XNo=" AND (url_query CONTAINS malformed_pattern OR url_query LENGTH abnormal)