CVE-2020-10042
📋 TL;DR
A buffer overflow vulnerability in Siemens SICAM MMU, SGU, and T web applications allows attackers with network access to execute arbitrary code. This affects all versions of SICAM SGU and specific older versions of MMU and T devices. The vulnerability enables remote code execution with high impact.
💻 Affected Systems
- SICAM MMU
- SICAM SGU
- SICAM T
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise allowing attacker to execute arbitrary code, potentially gaining full control of affected devices, disrupting industrial operations, and pivoting to other network segments.
Likely Case
Remote code execution leading to device compromise, data theft, or disruption of industrial control system operations.
If Mitigated
Limited impact if devices are isolated in protected networks with strict access controls and monitoring.
🎯 Exploit Status
Buffer overflow vulnerabilities typically have low exploitation complexity, especially when network-accessible.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: SICAM MMU: V2.05 or later, SICAM T: V2.18 or later, SICAM SGU: No fixed version available (consider mitigation strategies)
Vendor Advisory: https://cert-portal.siemens.com/productcert/pdf/ssa-305120.pdf
Restart Required: Yes
Instructions:
1. Download updated firmware from Siemens support portal. 2. Backup device configuration. 3. Apply firmware update following Siemens documentation. 4. Verify update completion and restore configuration if needed.
🔧 Temporary Workarounds
Network Segmentation
allIsolate affected devices in protected network segments with strict firewall rules.
Access Control
allRestrict network access to web interfaces using firewall rules and authentication.
🧯 If You Can't Patch
- Implement strict network segmentation and firewall rules to limit access to affected devices
- Deploy intrusion detection systems to monitor for exploitation attempts
🔍 How to Verify
Check if Vulnerable:
Check device firmware version via web interface or CLI and compare against affected versions.Check Version:
Device-specific commands vary; typically accessible via web interface or serial console.Verify Fix Applied:
Verify firmware version is updated to patched versions: MMU ≥ V2.05, T ≥ V2.18.📡 Detection & Monitoring
Log Indicators:
- Unusual web application access patterns
- Buffer overflow error messages in device logs
- Unexpected process execution
Network Indicators:
- Unusual traffic to web application ports (typically 80/443)
- Malformed HTTP requests to device web interfaces
SIEM Query:
source_ip="*" AND dest_port IN (80, 443) AND dest_ip="[device_ip]" AND http_request CONTAINS "buffer" OR "overflow"