CVE-2021-41546
📋 TL;DR
This vulnerability affects Siemens RUGGEDCOM ROX industrial network devices, allowing attackers to cause permanent denial-of-service by exploiting improper filesystem space checking during crashdump creation. When exploited, it fills the root filesystem completely, preventing affected devices from booting successfully. All versions before V2.14.1 of multiple RUGGEDCOM ROX models are vulnerable.
💻 Affected Systems
- RUGGEDCOM ROX MX5000
- RUGGEDCOM ROX RX1400
- RUGGEDCOM ROX RX1500
- RUGGEDCOM ROX RX1501
- RUGGEDCOM ROX RX1510
- RUGGEDCOM ROX RX1511
- RUGGEDCOM ROX RX1512
- RUGGEDCOM ROX RX1524
- RUGGEDCOM ROX RX1536
- RUGGEDCOM ROX RX5000
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Permanent device bricking requiring physical replacement, causing extended operational downtime in industrial environments.
Likely Case
Extended denial-of-service requiring manual intervention and potential device re-imaging or replacement.
If Mitigated
Limited impact with proper monitoring and quick response to crash events.
🎯 Exploit Status
Exploitation requires ability to trigger crashdumps, which typically requires some level of access or ability to cause system instability.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: V2.14.1
Vendor Advisory: https://cert-portal.siemens.com/productcert/pdf/ssa-173565.pdf
Restart Required: Yes
Instructions:
1. Download firmware V2.14.1 from Siemens support portal. 2. Backup device configuration. 3. Apply firmware update via web interface or CLI. 4. Reboot device. 5. Verify version is V2.14.1 or higher.
🔧 Temporary Workarounds
Monitor filesystem usage
linuxImplement monitoring to alert when filesystem usage exceeds thresholds, allowing intervention before full disk condition.
# Monitor / filesystem usage
df -h /
# Set up SNMP monitoring for disk usage
Disable crashdump generation
allIf supported by device configuration, disable automatic crashdump generation to prevent filesystem filling.
# Check device documentation for crashdump disable commands
# Typically via CLI or web interface configuration
🧯 If You Can't Patch
- Implement strict network segmentation to limit access to affected devices
- Deploy network monitoring to detect crashdump generation attempts and filesystem filling patterns
🔍 How to Verify
Check if Vulnerable:
Check device firmware version via web interface or CLI. If version is below V2.14.1, device is vulnerable.Check Version:
show version (CLI) or check System Information in web interfaceVerify Fix Applied:
Verify firmware version is V2.14.1 or higher and monitor for successful boot cycles without filesystem filling issues.📡 Detection & Monitoring
Log Indicators:
- Repeated crashdump generation events
- Filesystem full errors in system logs
- Failed boot attempts
Network Indicators:
- Unusual traffic patterns to trigger crashes
- Multiple connection attempts to crash-related services
SIEM Query:
source="*ruggedcom*" AND ("crashdump" OR "filesystem full" OR "boot failure")