CVE-2022-26334
📋 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. This impacts industrial control systems using these switches.
💻 Affected Systems
- SCALANCE X302-7 EEC series
- SCALANCE X304-2FE
- SCALANCE X306-1LD FE
- SCALANCE X307-2 EEC series
- SCALANCE X307-3 series
- SCALANCE X308-2 series
- SCALANCE X310 series
- SCALANCE X320 series
- SCALANCE X408-2
- SCALANCE XR324 series
- SIPLUS NET SCALANCE X308-2
📦 What is this software?
Scalance Xr324 4m Poe Ts 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.
Likely Case
Denial of service affecting network connectivity for connected industrial devices, requiring manual intervention to restore service.
If Mitigated
Minimal impact if devices are behind firewalls with restricted HTTP access and proper network segmentation.
🎯 Exploit Status
Simple HTTP request manipulation required. No authentication needed. Technical details are documented in Siemens advisory.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Check Siemens advisory for specific firmware versions
Vendor Advisory: https://cert-portal.siemens.com/productcert/pdf/ssa-836527.pdf
Restart Required: Yes
Instructions:
1. Download updated firmware from Siemens Industrial Network Management. 2. Backup current configuration. 3. Upload new firmware via web interface or management software. 4. Reboot device. 5. Verify firmware version and functionality.
🔧 Temporary Workarounds
Disable HTTP interface
allDisable the HTTP management interface if not required, forcing use of HTTPS or other management protocols.
Configure via web interface: System > Security > HTTP/HTTPS > Disable HTTP
Restrict network access
linuxImplement firewall rules to restrict HTTP access to management interfaces from trusted networks only.
iptables -A INPUT -p tcp --dport 80 -s trusted_network -j ACCEPT
iptables -A INPUT -p tcp --dport 80 -j DROP
🧯 If You Can't Patch
- Segment affected switches in isolated network zones with strict firewall rules
- Implement network monitoring for abnormal HTTP requests to device management interfaces
🔍 How to Verify
Check if Vulnerable:
Check firmware version against Siemens advisory. Devices with unpatched firmware are vulnerable if HTTP interface is enabled.Check Version:
Via web interface: System > Device Information > Firmware VersionVerify Fix Applied:
Verify firmware version matches patched version from Siemens advisory and test HTTP interface functionality.📡 Detection & Monitoring
Log Indicators:
- HTTP requests with malformed XNo parameter
- Device crash/reboot events in system logs
- Unusual HTTP traffic to switch management interfaces
Network Indicators:
- HTTP GET requests with abnormal XNo parameter values
- Sudden loss of connectivity to affected switches
SIEM Query:
source="switch_logs" AND (http_request="*XNo=*" OR event="device_reboot")